Nice try.
Was Germany part of the United States?
The parts under US occupation?
What is the meaning of “part”?
Back in the Cold War, for a while there even Konrad Adenauer said West Germany was a client state of the US.
Is Guam a part of the United States? I’m guessing you would say yes.
Was it a part of the United States the day the US Navy imposed a military governor on this conquered territory in 1898?
These are all complicated, fuzzy concepts.