I would continue to identify myself as "American" if USA broke up and each state became it's own country regardless of whether I went abroad prior to that or any other situation of that sort.

Some states that cause residents to have conversations like this:

Me: "I'm American. Freedom flavored." (don't make assumptions, anyone from North or South America is American) You: "Cool, which state?" Me: "A united state!" You: "What in the actual fuck? They're all united. What specific state do you reside in and/or originate from? (Smartass...)" Me: "Look... If you sweat all the small shit you're gonna die from a heart attack in your 50s." You: "Holy shit... So... Florida?" Me: "Worse." You: "Ah... Question retracted."