Ok, This is a legal question ... but I know that it has lots of political implications ... but I interested in the legal side of it.

IF all it takes is a act of congress to make DC a state, could an act of congress in 4 years "unmake" DC a state?

I would have thought this was one of these things that requires a super majority or a constitutional convention or something.

Can an act of congress remove statehood from any state? Could Congress vote California or Texas out?

My constitution law is not really strong.