The process by which the U.S. president may veto a bill by not signing it. A bill normally becomes law ten days (excluding Sundays) after it is submitted to the president for signature, if Congress is still in session. If Congress adjourns within that ten-day period, without the president having signed the bill, the bill is killed. A pocket veto cannot be overridden by a two-thirds vote in the Senate, as is the case with other presidential vetoes.