Yes, that's ridiculous. But I'm interested in hearing you flesh out this scenario more.
Flesh out what, acts of terrorism by muslim extremists? Yeah I guess you're right, that could never happen except for all the times it did happen and will continue to happen.
The one where America bans guns and that is what opens the floodgates to a mass ISIS invasion whereby we are all slaughtered.
It'd have to involve a massive ship-building operation by ISIS, after they capture a few ports, and then mass training of their fighters as naval personnel, then the fleet sailing through the Mediterranean unstopped, past Gibraltar somehow, 3,000 miles across the Atlantic while the American Navy is (apparently?) distracted by something shiny, a landing on American shores where they can safely debark their troops while the Navy, Coast Guard, Army and Marines are tied up in a back room, Lassie is unable to go get help, and Chuck Norris is otherwise occupied.
In this scenario, the Air Force doesn't exist, because I can't figure out how they don't bomb the whole fleet to smithereens.
After that all happens - which is likely, you have to admit - at that point, Joe Average Citizen, America!, is going to have to drive those radical Muslims from our sacred shores.
I guess.