The diplomatic history of the United States oscillated among three positions: isolation from diplomatic entanglements of other (typically European) nations (but with economic connections to the world); alliances with European and other military partners; and unilateralism, or operating on its own sovereign policy decisions. The US always was large in terms of area, but its population was small, only 4 million in 1790. Population growth was rapid, reaching 7.2 million in 1810, 32 million in 1860, 76 million in 1900, 132 million in 1940, and 316 million in 2013. Economic growth in terms of overall GDP was even faster. However, the nation's military strength was quite limited in peacetime before 1940.
Brune (2003) and Arthur M. Schlesinger, Jr., ed. The Almanac of American History (1983) have specifics for many incidents.
1776 – Thirteen United Colonies declared independence as the United States of America on July 2; Declaration of Independence adopted on July 4
1776 – Three commissioners sent to Europe to negotiate treaties. Britain bans trade with the Thirteen Colonies, and the Second Continental Congress responds by opening American ports to all foreign vessels except from Great Britain. The Second Continental Congress also adopts the Model Treaty as a template for any future trade agreements with European countries such as France and Spain.
1776 – Treaty of Watertown, the first treaty by the independent United States, is signed establishing a military alliance with the Miꞌkmaq tribe.
1784 – British allow trade with America but forbid some American food exports to West Indies; British exports to America reach £3.7 million, imports only £750,000; imbalance causes shortage of gold in US.
— May 7 Congress votes to begin negotiations with Morocco.
— October 11 Moroccan corsair seizes the American ship Betsey and enslaves the crew; the Moroccans demand that the US pay a ransom to release the crew and a treaty to pay tribute to avoid future such incidents.
1785 – Adams appointed first minister to Court of St James's (Great Britain); Jefferson replaces Franklin as minister to France.
— March 11 Congress votes to appropriate $80,000 to pay in tribute to the Barbary states of Morocco, Algiers, Tunis and Tripoli.
— July 9 The Moroccans release the Betsy and her crew.
— July 25 Algerine pirates seizes the American ship Maria off the coast of Portugal; Algiers declares war on the US, and the dey Muhammad V of Algiers demands that the US pay $1 million in tribute to end the war.
— September, changed to Department of State; Jefferson appointed; John Jay continues to act as foreign affairs secretary until Jefferson's return from France; from 1789 to 1883. Much of the routine overseas business is the responsibility of navy officers.
1791 – In response to the beginning of the Haitian Revolution, Secretary of State Thomas Jefferson proposes limited aid to help suppress the revolt but also pressures the French government to reach a settlement with the Haitian revolutionaries.
— February 22 Congress votes to send another team of diplomats to Algiers to pay a ransom for the enslaved Americans and to negotiate a tribute treaty.
1793–1815 – Major worldwide war between Great Britain and France (and their allies); America neutral until 1812 and demands the right to do business with both sides
1794 -:— March 20 Congress votes to establish a navy and to spend $1 million building six frigates. Birth of the United States Navy.
— June 24 Jay Treaty with Britain. Averts war, opens 10 years of peaceful trade with Britain, fails to settle neutrality issues; British eventually evacuate western forts; boundary lines and debts (in both directions) to be settled by arbitration. Barely approved by Senate (1795) after revision; intensely opposed, became major issue in the formation of First Party System.
— September 5 United States signs a treaty agreeing to pay tribute to Algiers in exchange for which the dey Ali Hassan will free the 85 surviving American slaves. The treaty with Algiers is considered a national humiliation.
— President Adams asks Congress to spend more money on the navy and to arm American merchantmen in response to the Barbary pirate attacks.
— August 28 Treaty of Tripoli; treaty with Barbary state of Tripoli approved unanimously by Senate and signed into law by President John Adams on June 10; states "the Government of the United States of America is not, in any sense, founded on the Christian religion."
 The beginning of the First Barbary War. President Jefferson does not ask Congress for a declaration of war against Tripoli, but instead decides to begin military operations against Tripoli, arguing that the President has the right to begin military operations in self-defense without asking for permission from Congress.
— July 24 An American naval squadron begins the blockade of Tripoli.
— August 1 The U.S.S. Enterprise takes the Tripolitan ship Tripoli.
— April 18 Second American naval squadron sent to the Mediterranean.
— June 19 Morocco declares war on the United States.
1803 – Louisiana Purchase from France for $15,000,000; financed by sale of American bonds in London, and shipment of gold from London to Paris.
— June 2 Captain David Porter leads raid into Tripoli; first American amphibious landing in the Old World.
— February 23 The American diplomat William Eaton meets with Hamet Karanmanli, the exiled brother of the pasha Yusuf Karamanli of Tripoli in Egypt and agrees that the US will depose Yusuf and put Hamet on the throne; the first American effort at "regime change".
— March 8 A force of American sailors, marines, Tripolian exiles and Egyptian mercenaries under the leadership of Eaton leaves Alexandria with the aim of deposing pasha Yusuf of Tripoli.
— April 28 Eaton's force takes Derna, the road is wide open to Tripoli.
— June 4 Tripoli and the US sign a peace treaty.
1806 – Essex Case; British reverse policy and seize American ships trading with French colonies; America responds with Non-Importation Act stopping imports of some items from Great Britain
— June 28 Commodore Stephen Decatur arrives off Algiers, after threatening bombardment, the dey agrees to a peace treaty two days later in which he releases the American slaves and agrees to the end of the United States's tributary status.
1819 – Adams-Onís Treaty: Spain cedes Florida to America for $5,000,000; America agrees to assume claims against Spain, America gives up claims to Texas.
1823 – Monroe Doctrine. British propose America join in stating that European powers will not be permitted further American colonization. President James Monroe states it on December 2 as independent American policy.
1850 – Clayton–Bulwer Treaty. America and Great Britain agreed that both nations were not to colonize or control any Central American republic, neither nation would seek exclusive control of Isthmian canal, if canal built protected by both nations for neutrality and security. Any canal built open to all nations on equal terms.
1853 – Gadsden Purchase: purchase of 30,000 square miles (78,700 km2) in southern Arizona for $10,000,000 for purpose of railroad connections
1854 – Kanagawa Treaty; Matthew Perry to Tokyo in 1853; returning 1854 with seven warships; treaty opened two Japanese ports and guaranteeing the safety of shipwrecked American seamen.
1861 – 13 May. Britain issues a proclamation of neutrality, and recognizes the belligerent rights of the Confederacy. However, it does not recognize the Confederate government.
1864–65 – Maximilian Affair: In defiance of the Monroe Doctrine, French Emperor Napoleon III placed Archduke Maximilian on Mexican throne and French army suppresses Mexican resistance. Washington warns France against intervention, with 50,000 combat troops sent to the Mexican border; France withdraws. Mexicans overthrow and execute Maximilian.
1893 – Hawaii; January 16 to April 1. Local businessmen revolt against Queen Liliuokalani attempt to impose an absolute monarchy. The overthrow the Queen with no violence and proclaim provisional government; US Marines landed to protect American lives; New government and President Harrison agree to annexation but treaty withdrawn (1893) by President Grover Cleveland. The new government declares a Republic of Hawaii.
1895 – Venezuela Crisis of 1895 is a dispute with Britain over the boundary of Venezuela and a British colony; it is finally settled by arbitration.
1897 – The Olney-Pauncefote Treaty of 1897 is a proposed treaty with Britain in 1897 that required arbitration of major disputes. Despite wide public and elite support, the treaty was rejected by the US Senate, which was jealous of its prerogatives, and never went into effect.
1897–98 – American public opinion is outraged by news of Spanish atrocities in Cuba. President McKinley demands reforms.
1898 – De Lôme Letter: Spanish minister to Washington writes disparagingly of President McKinley, casting doubt on Spain's promises to reform its role in Cuba
— Treaty of Paris; US gains Philippines, Guam and Puerto Rico; pays Spain for claims; Cuba comes under temporary US control
— Hawaii seeks to join US; with votes lacking for 2/3 approval of a treaty on July 7. The Newlands Resolution in Congress annexes the Republic of Hawaii, with full US citizenship for Hawaiian citizens regardless of race
1901 – Congress passes Platt Amendment, designed to protect Cuba's independence from foreign intervention. It effectively makes Cuba a US protectorate and allowed for American intervention in Cuban affairs in 1906, 1912, 1917, and 1920. It also permitted Washington to lease Guantanamo Bay Naval Base. Rising Cuban nationalism and widespread criticism led to its abrogation in 1934 by the Ramón Grau administration.
1903 – Big Stick diplomacy: Theodore Roosevelt refers to US policy as "speaking softly and carrying a big stick", applied the same year by assisting Panama's independence movement from Colombia. US forces sought to protect American interests and lives during and following the Panamanian revolution over construction of the Isthmian Canal. US Marines were stationed on the isthmus (1903–1914)
1912–41 – China. US forces sent to protect American interests in China during chaotic revolution. In 1927, America had 5,670 troops ashore in China (mostly Marines) and 44 small naval vessels in its rivers.
1913–15 – Secretary of State William Jennings Bryan negotiates 28 treaties that promised arbitration of disputes before war broke out between the signatory countries and the United States. He made several attempts to negotiate a treaty with Germany, but ultimately was never able to succeed. The agreements, known officially as "Treaties for the Advancement of Peace," set up procedures for conciliation rather than for arbitration.
1914 – Veracruz Incident a standoff between America and Huerta; Congress authorizes force at president's discretion; ABC Powers try to mediate; America seizes Veracruz; Huerta breaks diplomatic relations; war seems near
1915 – British passenger liner RMS Lusitania torpedoed off Irish coast by German submarine without warning in defiance of international law that requires giving passengers an opportunity to board lifeboats; 1,200 dead include 128 Americans; Theodore Roosevelt demands war with Germany; Woodrow Wilson issues strong protest.
1915–34 – Haiti. US forces maintained order and control customs revenue during a period of chronic political instability.
1916–24 – Dominican Republic; US naval forces maintained order and control customs revenue during a period of chronic and threatened insurrection.
1924 – American-led conference results in the Dawes Plan. Eased reparations for Germany and improvement of its economic situation.
1924 – Rogers Act establishes the Foreign Service by merging the low-paid high prestige diplomatic service with the higher paid, middle class consul service. The act provided a merit-based career path, with guaranteed rotations and better pay.
1926–33 – Nicaragua; The coup d'état of General Emiliano Chamorro Vargas aroused revolutionary activities leading to the landing of US Marines intermittently until January 3, 1933.
1927 – Naval Disarmament Conference in Geneva; failure to reach an agreement.
1937 – Japan invades China, with full-scale war and many atrocities against Chinese; Japan conquers major cities and seacoast; Americans strongly sympathetic to China; Roosevelt does not invoke neutrality laws
1938 – Munich Pact sacrifices Czechoslovakia to Nazi Germany in the name of appeasement; US not involved but does not object
1940– American intelligence breaks the Japanese diplomatic code with MAGIC.
— July 29 Japan occupies the southern half of French Indochina, seen as a threatening move.
— July 30 US together with Britain and the Dutch government in exile imposes trade embargo against Japan, most crucially in oil.
— August 13 Atlantic Charter. Anglo-American summit off the coast of Newfoundland. Roosevelt and Winston Churchill agree (1) no territorial gains sought by America or Great Britain, (2) territorial adjustments must conform to people involved, (3) people have right to choose their own govt. (4) trade barriers lowered, (5) there must be disarmament, (6) there must be freedom from want and fear ("Four Freedoms" of FDR), (7) there must be freedom of the seas, (8) there must be an association of nations. Charter is accepted by Allies, who call themselves "the United Nations".
— October 31 American destroyer USS Reuben James sunk by a U-boat. Rise in German-American tensions.
— December 6 American intelligence fails to predict attack on Pearl Harbor.
— December 11 Germany and Italy declare war on the U.S.
1942 -:— August 8 Riegner Telegram received in Washington. Gerhart M. Riegner of the World Jewish Congress has received reliable information that Germany is engaged in a campaign of extermination against the Jews of Europe.
— January Casablanca Conference. Roosevelt and Churchill meet to plan European strategy. Unconditional surrender of Axis countries demanded, Soviet aid and participation, invasion of Sicily and Italy planned
— October 30 Moscow Declaration. Joint statement by the United States, United Kingdom and the Soviet Union promises that German leaders will be tried for war crimes after the Allied victory.
— November Cairo Conference. Roosevelt, Churchill and Chiang Kai-shek meet to make decisions about postwar Asia: Japan returns all territory, independent Korea.
1945 – June 26 – United Nations Charter signed in San Francisco. America becomes a founding member and has veto power on the Security Council along with Great Britain, France, China and the Soviet Union.
1945 – August—Nuclear bombing of Hiroshima and Nagasaki; surrender of Japan (V-J Day); beginning of the nuclear age.
1945–1953 – U.S. provides grants and credits amounting to $5.9 billion to Asian countries, especially China/Taiwan ($1.051 billion), India ($255 million), Indonesia ($215 million), Japan ($2.44 billion), South Korea ($894 million), Pakistan ($98 million) and the Philippines ($803 million). In addition, another $282 million went to Israel and $196 million to the rest of the Middle East. All this aid was separate from the Marshall Plan.
1946 – In the Blum–Byrnes agreement, the US forgives $2.8 billion in French debts (mostly World War I loans), and gives an additional low-interest loan of $650 million. In turn, France allows American films in its cinemas.
1947 – Truman Doctrine gives military and economic aid to Greece and Turkey to halt spread of Communism
1947–1989 – Cold War, an era of high tension and hostility—but no major "hot" war—between the US and its allies (Western Europe, Canada, Japan, etc.) and the Soviet Union and its satellite states.
1948–1951 – Marshall Plan (formally, "European Recovery Plan"); US gives out $13 billion to rebuild and modernize Western European economies. Increased trade between Europe and the America; no repayment asked for.
— June 24 Berlin Blockade imposed by the Soviet Union, blocking traffic into western sectors of Berlin, followed by Operation Vittles, America airlifted massive amounts of food, fuel and supplies into city. Soviet blockade lifted on May 12, 1949.
— January 21 Dean Acheson appointed Secretary of State. He will hold this office until 1953 and is remembered as one of the more abler Secretaries of State.
— April 4 America and eleven other nations sign the North Atlantic Treaty, creating NATO, a military alliance with the purpose of countering the Soviet Union and its allies.
— 23 May 1949 The United States, Britain and France grant independence in their zones in Germany to a new state called the Federal Republic of Germany.
— June 25 Korean War begins. US sends in troops to stop North Korean invasion; UN votes support; (Soviet Union boycotted UN and did not veto.) US forces deployed in Korea exceeded 300,000 during the last year of the conflict.
— September US-led invasion defeats North Korean army; UN authorizes rollback strategy, with North Korea to come under UN control
— November Chinese forces enter North Korea; roll back UN-US-South Korean forces to below 38th parallel
— March 28 President Vincent Auriol of France visits Washington to meet President Truman. During his visit, the US agrees to pay for entire French war effort in Vietnam, and to provide unlimited military aid.
— April President Truman fires General Douglas MacArthur as blame game escalates regarding Korean war stalemate.
— June Talks for an armistice in the Korean War open. The major issue that divides the Communist and UN sides is the return of the POWs with the Communists demanding that all POWs from their nations be repatriated while the UN insists on voluntary repatriation.
— September 1 ANZUS Treaty united America, Australia and New Zealand in a defensive regional pact
1952 – Dwight D. Eisenhower defeats isolationist element in GOP; denounces stalemate in Korea and promises to go there himself; elected president in landslide
— May Eisenhower threatens use of nuclear weapons in Korean War; China agrees to negotiate.
— July 27 armistice signed ending the Korean War (it is still in effect).
— March 13 The Battle of Dien Bien Phu begins. As the French are faced with defeat in Vietnam, Eisenhower considers intervention with tactical nuclear weapons to break the siege of Dien Bien Phu, and orders the Joint Chiefs of Staff to start work on Operation Vulture, the plan to intervene in Vietnam. Operation Vulture is ultimately rejected as a policy option.
— April 26 Geneva conference opens. Through called to consider a peace treaty for the Korean War, the conference is soon dominated by the question of Vietnam. The Secretary of State John Foster Dulles heads the American delegation.
— July 20 The Geneva conference closes with an agreement on the partition of Vietnam into two states with a promise to hold a general election in both by June 1956. Dulles does not sign the Geneva accords, but promises that the US will abide by them.
1957 – Eisenhower Doctrine gives the president authority to determine the necessity to assist any nation requesting assistance against armed aggression from any country controlled by international communism, applied in Lebanon the following year.
1962 – Cuban Missile Crisis. John F. Kennedy on October 22 announces that there exist Soviet missiles in Cuba and demanded their removal while imposing an air-sea blockade. Soviet missiles are withdrawn on condition that America will not invade Cuba.
1963 – Partial Nuclear Test Ban Treaty. US and the Soviet Union agreed not to conduct nuclear tests in space, in the atmosphere or underwater. Underground tests permitted; signed by 100 nations, excluding France and the People's Republic of China.
— January 28 Nixon launches policy of Vietnamization, in which American ground troops in Vietnam were to be steadily reduced and the American role was to provide military training, equipment, and air support for the South Vietnamese military. Vietnamization was intended to reduce American losses in Vietnam, and thus reduce the domestic pressure for a total withdrawal of American forces. At the same time Nixon intensified the war by beginning Operation Menu, the secret bombing of Cambodia. Nixon's aim in Vietnam is to force a Korean War-type armistice, which requires that the war go on until Hanoi agreed to the American terms while at the same time forcing Nixon to deflect pressure from domestic anti-war protests. With the same aim of achieving an armistice that would allow South Vietnam to continue to exist, Nixon begins a policy of seeking better relations with the Soviet Union and China, hoping those two states would reduce, if not end their arm supplies to North Vietnam in return for better relations with Washington, and thus forcing Hanoi to accept peace on American terms.
— February Following the success of the first "accelerated pacification" and the Phoenix Program of "neutralizing" (i.e. assassinating) Viet Cong operatives, Nixon applies strong pressure for more "accelerated pacification" campaigns and the Phoenix Program killings in South Vietnam as a part of the effort at breaking the Viet Cong. For Nixon, "accelerated pacification" and the Phoenix Program killings both have the effect of weakening the Viet Cong without the use of American troops, which serves to achieve both his aims of reducing American forces and applying pressure for the Vietnamese Communists to accept peace on American terms.
— March 8 President Nasser of Egypt launches the War of Attrition against Israel. The US supports Israel while the Soviet Union supports Egypt.
— July 25 Nixon announces the Nixon Doctrine in which Nixon warns that the United States will not go to any lengths to defend its allies, especially in Asia, and henceforth American allies must do more for their own defense. The doctrine is especially aimed at South Vietnam and is intended to pressure the South Vietnamese government to do a more effective job of fighting the Communists.
— July Nixon visits Pakistan and meets with the Pakistani President General Agha Yahya Khan, tells him that he wants to use Pakistan as an intermediary for talks with China. Yahya Khan agrees to Nixon's request.
— September 9 Walter Stoessel, the American ambassador to Poland is ordered by Nixon to make contacts with Chinese diplomats in an informal way.
— October 16 Pakistani ambassador to the United States Agha Hilaly tells Kissinger that President Yahya is going to visit China early the next year, and is there any message that Kissinger would like Yahya to pass on to Mao.
— November 3 Nixon gives a TV speech claiming that there was a "silent majority" supporting his Vietnam policies, states that he needs some more time for his policies to work, denounces anti-war protestors as a threat to world peace, and asks for the support of the "silent majority" to help him "to end the war in a way that we could win the peace."
— February 23 Hilaly tells Kissinger that after Yahya's visit to Beijing that the Chinese were interested in the American offer, but did not want to negotiate from a position of weakness.
— March Under the "accelerated pacification", more than million hectares of land have been redistributed in American-encouraged land reform in South Vietnam.
— March 7 Chiang Kai-shek who has heard reports of Sino-American talks in Warsaw writes to Nixon to protest.
— April 29 Nixon orders the Cambodian Incursion. American and South Vietnamese force invade eastern provinces of Cambodia with the aim of clearing out the Viet Cong/North Vietnamese forces based there. Sparks much protest in the United States.
— June By this point in the War of Attrition between Israel and Egypt, there are regular clashes occurring between Israel and Soviet forces in Egypt, leading to fears that this might cause a world war, which in turn leads to strong pressure for a ceasefire.
— October 25 During a Pakistani-American summit, President Nixon asks President Yahya to pass on another message to Beijing about the American wish for rapprochement with China.
— October 31 Kissinger meets with Romanian President Nicolae Ceaușescu and asks him to pass on a message to China that the US wishes for a normalization of relations with the People's Republic of China.
— January 12 Corneliu Bogdan, the Romanian ambassador to the US tells Kissinger that Ceaușescu has passed on the American message, and that for Mao, normalization would be possible if the US would end the "occupation" of Taiwan as Mao calls American support for Taiwan. This poses a major problem for Nixon as allow China to take Taiwan would greatly damage America's image and pose domestic problems.
— March 4 Nixon gives press conference, and warns that better Sino-American relations cannot come at the expense of Taiwan.
— March 26 Pakistan launches Operation Searchlight intended by President Agha Yahya Khan to crush the Awami League in East Pakistan, and to eliminate the intelligentsia, political class and Hindu minority of East Pakistan. As General Yahya is a key conduit in the talks between the US and China, the Nixon administration does not protest Operation Searchlight as it fears this might offend General Yahya, as part of its marked "tilt" towards Pakistan.
— April 6 The Blood telegram sent by Archer Blood, the American consul in Dhaka and 20 other diplomats protesting the Nixon administration's silence about the Pakistani government's repression in East Pakistan and what the telegram argues is a campaign of genocide by the government against the Hindu minority in East Pakistan. The Blood telegram does not affect American policy towards Pakistan, and effectively cuts the career of Blood and the other diplomats.
— April 14 Ping-pong diplomacy. The American table tennis team is allowed to visit China, causes a sensation. During a phone conversation, Kissinger says "It's a tragedy that it has to happen to Chiang at the end of his life but we have to be cold about it", to which Nixon replies "We have to do what's best for us".
— April 21 Pakistani President Yahya informs Nixon that he had spoken with Zhou Enlai, and that the Chinese wished for a senior American envoy to make a secret visit to Beijing.
— April 27 About the Chinese offer of a secret American envoy to visit Beijing, Kissinger tells Nixon that "If we get this thing working, we will end Vietnam this year."
— July 9 Kissinger visits Islamabad, Pakistan, and from there goes on to a secret trip to Beijing to meet Zhou Enlai and Mao Zedong. During the secret summit in Beijing, it is agreed that President Nixon will visit China the next year.
— December 3 Indo-Pakistani war begins. The US supports Pakistan while the Soviet Union supports India.
— December 11 Nixon orders Task Force 74 to the Bay of Bengal in an attempt to intimidate India into accepting a ceasefire before the Indians defeat Pakistan.
— December 16 The war ends in Pakistan's defeat. Nixon fails in his efforts preserve Pakistan's unity, and East Pakistan secedes as the independent People's Republic of Bangladesh.
— October 6 October War begins with a surprise attack on Israel by Egypt and Syria. The US supports Israel while the Soviet Union supports Egypt and Syria.
— October 12 Nixon orders Operation Nickel Grass, a major American effort to supply Israel with weapons to make good the IDF's heavy initial losses.
— October 20 Arab oil embargo led by King Faisal of Saudi Arabia against the US and other Western nations begins as punishment for support of Israel. The oil embargo sparks major inflation in the United States.
— October 24 The Soviet Union announces that it will send troops to Egypt, which in turn leads Kissinger to warn that the United States will send troops to fight the Soviet forces deployed to Egypt. Nixon places the United States military on DEFCON 3, one of the highest states of alert. The Soviets back down.
— October 25 A ceasefire brokered by the US and the Soviet Union ends the October War.
— January 18 Under an American disengagement plan negotiated by Kissinger, Israeli forces pull back from the Suez Canal.
— March 17 Arab oil embargo against the West ends.
1979–81 – Iran becomes an Islamic republic after the overthrow of American-backed Shah; militants seize 63 American diplomats for 444 days during the Iran hostage crisis; America seizes $12 billion in Iranian assets; American rescue effort fails; hostages and assets are freed on January 20, 1981.
1980–88 – Iran–Iraq War. America officially neutral in the war between Iraq and Iran; America flags oil tankers to protect flow of oil in Persian Gulf, and sells arms and weaponry to both sides of the conflict.
1981 – President Ronald Reagan escalates Cold War with heavy new military spending and research in new weapons; forward strategy for Navy.
— September 29 MNF comprising forces from the United States, France, and Italy set to Lebanon to stabilize the nation in the middle of its civil war.
— April 18 A suicide attack by the Iranian-supported Hezbollah terrorist group destroys the American embassy in Beirut.
— April 5 La Belle discotheque in Berlin bombed by Libyan agents. The discotheque is popular with American servicemen and two out of the three killed are American. As the NSA has broken the Libyan diplomatic codes, it is established that the bombing was planned out of the Libyan "people's bureau" (embassy) in East Berlin.
— November The news of the Iran–Contra affair breaks: White House officials sell weapons to Iran and give the profits to Contras; President Reagan embarrassed.
— June 12 President Reagan gives the "Tear down this wall!" speech in Berlin, saying "Mr. Gorbachev, tear down this wall!". Reagan argues that tearing the Berlin Wall would be a symbol of Soviet good faith to prove Gorbachev was sincere in seeking better relations with the West.
1989 – End of Eastern Bloc; fall of Berlin Wall; all East European satellites break away from Moscow
— September 12 Four plus two treaty signed by the US, Britain, France, the Soviet Union, West Germany and East Germany formally ends World War II in Europe, grants the two German states the right to unify and ends all of the sovereign rights held by the Allies in Germany since 1945.
1991 – Gulf War; America leads a UN-authorized coalition to repel an Iraqi invasion out of neighboring Kuwait.
1991–2003 – Iraq sanctions; America and Great Britain maintain no-fly-zones in the north and south of Iraq with periodic bombings.
1991–93 – START II accords held by America and Russia to limit nuclear weapons
2009–2017 – The Foreign policy of the Barack Obama administration downplays Bush's counterinsurgency model against terrorism. Instead it uses a light-footprint approach with expanded air strikes, extensive use of special forces and greater reliance on host-government militaries.
2009 – President Obama lifts all travel restrictions to see relatives in Cuba and send remittances. However, later that year, Obama approved continuing the Trading with the Enemy Act, which regulates sanctions on Cuba.
2011 – US removes all military forces from Iraq
2011 – New START treaty with Russia goes into effect.
2011 – CIA uses Navy Seals against the highest priority terrorism target. They raid Al-Qaeda founder Osama bin Laden's compound in Pakistan, killing him and seizing his computers. Pakistan was not informed.
2013 – US threatens an air attack on Syria after it uses chemical weapons; resolved by agreement to destroy all the chemical weapons under international auspices
2017 – 2021 Foreign policy of the Donald Trump administration includes major shifts in foreign policy. It sounds alarm about development by North Korea of nuclear weapons and missiles that can hit North America. It gives high priority to combating terrorism, especially from radical Islam. It prioritizes military action and deemphasizes soft power, political engagement, and diplomacy. It calls for a high wall across the southern border.
2017 – US formally recognizes Jerusalem as the capital of Israel but does not move embassy yet. UN General Assembly condemns US plan by a vote of 128–9.
Findling, John, ed. Dictionary of American Diplomatic History 2nd ed. 1989. 700pp; 1200 short articles.
Folly, Martin and Niall Palmer. The A to Z of U.S. Diplomacy from World War I through World War II (2010) excerpt and text search
Herring, George. From Colony to Superpower: U.S. Foreign Relations since 1776 (Oxford History of the United States) (2008), 1056pp excerpt, a standard scholarly history; also published in updated two volume edition in 2017