US President Ronald Reagan signing a veto of a bill. A veto is a legal power to unilaterally stop an official action. In the most typical case, a president or monarch vetoes a bill to stop it from becoming law. In many countries, veto powers are established in the country's constitution.

In the United States, the president can use the veto power to prevent a bill passed by the Congress from becoming law. Congress can override the veto by a two-thirds vote of both chambers. All state and territorial governors have a similar veto power, as do some mayors and county executives.

The United Nations Security Council veto power is the power of the five permanent members of the UN Security Council (China, France, Russia, the United Kingdom, and the United States) to veto any decision other than a "procedural" decision.

If the President blocks legislation by pocket veto, Congress cannot later override the veto—instead, the legislature must reintroduce the bill and enact it again. The Supreme Court has explained that the Constitution’s veto provisions serve two functions.

2017年11月17日 · The veto power of the U.S. president is one way of preventing the legislative branch of the federal government from exercising too much power.

The Veto Power The veto provisions, the Supreme Court has told us, serve two functions. On the one hand, they ensure that “the President shall have suitable opportunity to consider the bills presented to him. . . .

The following essays discuss the veto power, including Supreme Court cases limiting the availability of line item vetoes and legislative vetoes. See ArtI.S7.C2.2 Veto Power; ArtI.S7.C2.3 Line Item Veto; ArtI.S7.C2.4 Legislative Veto.