How many days does the president of the U.S. have to veto a bill?

The U.S. Constitution grants the president 10 days (excluding Sundays) to review a measure passed by the Congress of United States. If the president has not signed the bill after 10 days, it becomes law without his signature. However, if Congress adjourns during the 10-day period, the bill does not become law. Under Article I, section 7 of the Constitution, the president is granted the authority to veto legislation passed by Congress. This authority is one of the most significant tools a president can employ to prevent a bill from becoming law.

Concerning bills (potential laws), they all face two types of vetoes: the “regular veto” and the “pocket veto.” The regular veto is a qualified negative veto. The president returns the unsigned legislation to the originating house of Congress within a 10 day period usually with a memorandum of disapproval or a “veto message.” Congress can then override the president’s decision if it musters the necessary two–thirds vote of each house.

The pocket veto is an absolute veto that cannot be overridden. The veto becomes effective when the president fails to sign a bill after Congress has adjourned and is unable to override the veto. The authority of the pocket veto is derived from the Constitution’s Article I, section 7, “the Congress by their adjournment prevent its return, in which case, it shall not become law.”