How can Congress override a presidential veto?

Congress can override a presidential veto with a two-thirds majority vote in both the House of Representatives and the Senate. This requirement is set by Article I, Section 7 of the Constitution. The two-thirds threshold is deliberately high, designed to give the President a meaningful check on legislation while still allowing strongly supported bills to become law over presidential opposition.

When the President vetoes a bill, it returns to the chamber where it originated, accompanied by a written message explaining the President's objections. That chamber holds a vote on whether to override. If two-thirds of members present and voting agree to override, the bill goes to the other chamber, which holds the same vote. If both chambers vote two-thirds to override, the bill becomes law without the President's signature.

Override votes are difficult to achieve. Of more than 2,500 vetoes in American history, only about 110 have been overridden. The first successful override came in 1845, when Congress overrode President John Tyler's veto of a revenue cutter authorization. Major recent override votes include the override of George W. Bush's veto of a Medicare bill in 2008 and the override of Donald Trump's veto of the National Defense Authorization Act in 2020 and 2021.

Two-thirds override votes typically require significant bipartisan support, since neither party has held a two-thirds majority in either chamber for many decades. This means override votes happen only on bills that command unusually broad agreement across party lines, often related to defense authorizations, override of pocket vetoes, or technical legislation.

The override mechanism is a central feature of the Constitution's checks and balances. It gives the President a meaningful veto power without making that power absolute, and it lets Congress have the final word on legislation if it can muster sufficient support. Critics argue the two-thirds threshold makes overrides too difficult, allowing presidents to block legislation supported by simple majorities in both chambers. Defenders argue the supermajority requirement protects against impulsive lawmaking and forces broader consensus on major legislation.