What is so wrong with identifying foremost as an American?
First, while this may not bother some, doing so is accepting the Galut (exile). Second if a Jew views themselves as an "American" first, then they will ultimately be killing themselves not only spiritually but also physically. I am quite sure that there will be a day when there will be a rise in anti-Semitism in America and ultimately there will likely be a Holocaust in America, perhaps not soon but someday. Because of that we must accept that we are Jews first because whether we want to admit it or not, our enemies will remind us, just like they did in Germany.
*I don't mean to offend any Righteous Gentile posters and I'm sure that you will stand by us even if the rest of America does someday rise against us but we (The Jews) must accept that we can't run away from our problems and pretend that a Holocaust can never happen again.