Confidence and Supply Agreement

A confidence and supply agreement (CSA) is a parliamentary arrangement used in Westminster-style systems and other parliamentary democracies when no single party wins a majority of seats. Under such an agreement, one or more smaller parties commit to backing a minority government on two specific categories of votes:

• Confidence motions — votes that, if lost, would force the government to resign or trigger an election.
• Supply — the appropriation bills and budgets that authorise government spending.

On all other legislation, the supporting party retains freedom to vote as it chooses, including against the government. This distinguishes a CSA from a formal coalition, in which parties share cabinet seats and are bound by collective responsibility across the full legislative programme.

CSAs typically set out, in writing or by convention, the policy concessions the minor party receives in exchange for its support, a duration (often the length of a parliamentary term), and consultation mechanisms between the parties' leaderships. They allow minor parties to extract policy wins without the electoral risks of governing, and let larger parties form stable administrations without diluting their cabinet.

Notable examples include the agreement between the UK Conservative Party and the Democratic Unionist Party following the June 2017 general election, which sustained Theresa May's minority government and reportedly included additional funding for Northern Ireland. In New Zealand, confidence and supply agreements have been a recurring feature of MMP-era governance, including arrangements between Labour and the Greens, and between National and smaller partners such as ACT and United Future across the 2000s and 2010s. Canada's Liberal–NDP "Supply and Confidence Agreement" announced in March 2022 is another prominent case, though it ended in September 2024 when the NDP withdrew its support.

CSAs trade governing power for legislative leverage, and their stability depends heavily on the personal trust between party leaders and the political cost of triggering an early election.