Powers and rights are interchangeable words in many circumstances; this is one of them.
The power of the president, for example, to veto a bill, is the right of the president to veto a bill.
Rights and powers are only interchangeable if you have never studied constitutional law. Anyone that got through high school civics should understand that the government has the power to enforce laws, it does not have the right to do so. People have the right to stand on a street corner and yell that the world is going to end in fire because of the Mayan calendar, they do not have the power to do so if they are smaller than the guy that is annoyed with them.
The power of the president to veto a bill has nothing to do with rights, it is spelled out in the constitution, and basically amounts to nothing more than a refusal to sign the bill. He must then return the bill to the chamber in which it originated along with a statement containing his objections.
A signing statement is not a right either, so stuff that one up your ass.
After you fold it with a lot of sharp corners.