The president vetoes bills. The president has the power to stop a bill from becoming a law. The president can refuse to sign a bill that Congress approved. This is called a veto. The bill is sent back to Congress without the president's signature. Congress can change the bill or vote again. If two-thirds of the House of Representatives and two-thirds of the Senate vote to override the veto, it becomes a law without the president's signature. The president vetoes bills.