I think "Bunge la Marekani" works; it just needs to be translated "U.S. Congress"
Hakuna bunge la Marekani!
Report it. Maybe someone will come along and add one. Or change the sentence, if that proves easier than altering the entire American political edifice. Whichever. ;)
It's not ungrammatical, just counterfactual. But "Parliament of USA" does seem kind of clumsy. "Parliament of the United States" or "American Parliament" would be better.
It makes as much sense as "Mfalme wa Ulaya." There is no King of Europe, sure, but it can be translated.