Analysts such as Harry Enten of FiveThirtyEight and Chris Cillizza of CNN interpreted the 2017 election results overall as demonstrating a move toward the Democratic Party. With the Democrats picking up the Senate seat in Alabama, it reduced the Republicans' majority in the Senate to 51–49. The analysts also noted that although none of five House seats held by a Republican switched to the other party in the 2017 special elections, in each race the Democrat received a higher percentage of votes than in recent elections for the same seat. Furthermore, Democrats made large gains in the Virginia House of Delegates, and picked up 42 seats in state legislatures.
The following special elections were held to replace Senators or Representatives who resigned in the 115th U.S. Congress:
Democrats also won control of the Washington Senate through a November special election. As part of a federal court ruling that invalidated its state legislative districts, the North Carolina General Assembly was ordered to hold special elections in the fall of 2017 with updated district lines. However, the US Supreme Court has put a hold on the 2017 election until it rules on the matter.
Two states held supreme court elections in 2017:
Pennsylvania held elections for three seats—one competitive election and two retention elections. In the Pennsylvania system, a justice must first be elected in a competitive race, and at the end of their term there is an up-or-down election on whether that justice should be retained.
A referendum regarding the political status of Puerto Rico was held on June 11. Puerto Rican voters were asked whether they prefer statehood, independence/free association, or maintain the current U.S. territorial status. This was the fifth such plebiscite overall, and the first one since 2012. Because there were almost 500,000 blank ballots in that 2012 referendum, creating confusion as to the voters' true desire, Congress decided to ignore that vote and then subsequently allocated funds for holding this 2017 one. 97% of the voters chose statehood in the referendum, though turnout was only at 23%.
Under the provisions of the New York Constitution, every twenty years the state is required to place before the voters a proposal to hold a constitutional convention to be held the following year, with any suggested amendments being voted on in the year after that. Therefore, in November 2017 a proposal was placed on the ballot for a 2018 convention, with any amendments to be voted on in 2019. On this vote, over 80% voted against a constitutional convention.
Various elections were held for officeholders in numerous cities, counties, school boards, special districts and others around the country. Below is a list of the mayoral elections held in the main cities of the United States:
Minneapolis, Minnesota: incumbent Democrat Betsy Hodges finished third and was eliminated after four rounds of vote tabulations. Fellow Democratic City Council member Jacob Frey was elected mayor, after finishing 1st place in all five rounds of vote tabulations.