Well they didn't just attack it (like Perl Harbor). They negotiated and tried for months to get all of the federal forts vacated. They were successful until Lincoln decided he wanted war and refused to give up this one.
If the current German government or British government were to tell us to vacate the US bases on their territory wouldn't we be obliged to go?
“If the current German government or British government were to tell us to vacate the US bases on their territory wouldn’t we be obliged to go?”
Not if such an action ran counter to our national security interests.