Who vetoes bills?

Why this is the answer

The President vetoes bills. A veto is the President's refusal to sign a bill that Congress has passed, and by itself it keeps the bill from becoming law. Article I, Section 7 describes how it works. The President returns the bill unsigned to the chamber where it started, along with the objections, and that chamber reconsiders it. The President has ten days to act. If Congress adjourns during those ten days and the President simply does nothing, the bill dies without ever being sent back; that quieter version is called a pocket veto. A veto is not always the last word. If two-thirds of the House and two-thirds of the Senate vote to pass the bill again, it becomes law without the President's signature. This is called overriding the veto, and it is not easy, because a bill normally passes with a simple majority but needs far more than that to survive a veto. Alexander Hamilton defended the power in Federalist No. 73. He called it a "qualified negative": the President can block a bill, subject to that two-thirds vote in each house. He gave it two purposes. It shields the President from a legislature tempted to absorb the powers of the other branches, and it adds protection against improper laws passed in haste or under the influence of faction. He expected Presidents to use it with great caution. On the test, answer "the President." Two wrong answers are easy to fall into. One is the Senate, which can block a treaty the President has signed, but rejecting a treaty is a different power from vetoing a bill. The other is the Supreme Court. The Court can reject a law passed by Congress, but by then the bill has already become law, while a veto stops it before that point. So the back and forth runs like this: Congress passes, the President can say no, and two-thirds of each chamber can still say yes.