Which branch of government can throw out a law?

Answer 1

This is a strange question, because I'm not sure I know what "throw out" means.

I think the answer you're looking for is the judicial branch. In the U.S., courts have the authority to declare laws unconstitutional, either violating the U.S. Constitution or a state constitution (which may have more protections than the federal constitution).

But there are other ways a law can be "thrown out." A president may veto a law that has been passed by both houses of congress. Of course, that's not technically a law, because to become a law, the bill must be passed by both houses and signed by the president (with certain limited exceptions).

And Congress can "throw out" a law by repealing it, that is, passing another law saying the first law is no more. That's what the Republicans are trying to do in the House right now with the health care reform law that has been passed.