To deport somebody, you have to have sufficient evidence and they cannot be local citizens or at least you cannot make them stateless.

Is there even any legal basis for exile?!

The US kills people by drone in other countries because they cannot legally do it in the US. In fact, they cannot legally do it in anybody else's country unless there is a declared state of war but that doesn't stop them! Pakistan gets a bit irate about that kind of stuff but it is very two-faced itself so I don't have that much sympathy.