Can President Trump sign repeal bill that Obama vetoed?

I obviously do not know. Is that even addressed anywhere? Is there and expiration date on law that the congress passed?

a reply to: Xeven

All bills expire at the end of the Congressional term that they were introduced in or passed in. That way, each Congress starts from scratch.

Once a bill is vetoed, it goes back to Congress. That specific Congress can then try to override the President's veto. But if they can't (or don't try because they know they don't have the votes), the leader of each Chamber of Congress will typically move on to other things. Then the bill will "die" once the new Congress is sworn into office, meaning that it will have to be reintroduced and re-passed before it goes back to the President's desk.

(I think that's completely correct. Someone else can chime in, too.)

a reply to: enlightenedservant

Perfect