In legislative debate, a wrecking amendment (also called a poison pill amendment or killer amendment) is an amendment made by a legislator who disagrees with the principles of a bill and who seeks to make it useless (by moving amendments to either make the bill malformed and nonsensical, or to severely change its intent) rather than directly opposing the bill by simply voting against it.[1]
An important character of wrecking amendments is that they are not moved in good faith, that is, the proposer of the amendment would not see the amended legislation as good legislation and would still not vote in favour of the legislation when it came to the final vote if the amendment were accepted. Motives for making them include allowing more debate, delaying the enactment of the legislation, or oftentimes a direct attempt to convince the bill's legislator to withdraw said bill.
Some opponents of particular amendments will describe them as wrecking amendments because they regard the amendments as undermining the unity of the original proposal. Proponents of the amendment may seek to deny the charge by saying that the original proposal brings together different steps, and while personally they oppose all the parts, some parts are even worse than others and legislators should have an opportunity to consider them separately.
Wrecking amendments can pick up more votes than motions against, because observers tend to focus on who voted in favour and against the Bill in the final count, rather than looking at the amendments made during the passage through the legislature.
In both Houses of the Parliament of the United Kingdom, the term "wrecking amendment" (also called "wrecking motion", "'reasoned amendment", or "reasoned motion") is also used to define a method by which MPs and Lords can put on record their opposition to a Bill. The amendment is made not to the Bill itself but to the motion that "the Bill be now read a second time" (or, more rarely, to the motion that "the Bill be now read a third time"); the amendment has the effect of replacing those words with "this House declines to give the Bill a Second Reading", often followed by the reasons for which, according to the amendment's proponent, the draft law should not be adopted; if the amendment passes, the bill is not reviewed any further and is removed from the list of Bills in progress.[2][3]
Leave out all the words after "That" and insert "this House declines to give the European Parliamentary Elections Bill a Second Reading on the grounds that it includes an undemocratic 'closed list' system providing for the selection of MEPs by party choice, an approach which would end the historic right of the British people to choose the candidates they wish to be elected, a step for which the House notes with great concern no mandate was sought or given at the last general election".
— An example of a reasoned amendment to the motion "That the Bill be read a second time".[4]
Another form of wrecking amendment to second or third reading is replacing the word "now" in the motion "that the Bill be now read a second time" with "upon this day six months" or "upon this day three months". This type of amendment, which has now fallen into disuse, is a legal fiction and is deemed by Erskine May's Manual as equivalent to a motion not granting the Bill a second reading at all.
A reasoned amendment differs from other types of proposed changes defined as "wrecking" because it is actually backed by the person introducing it.