Back in the 70's and 80's this was a common situation. We expel 4, they expel 4, they expel 25, we expel 25, etc. This is the way both sides try to flex their mussels. Give it a year and it will be forgotten about and they'll all be allowed back in. As for asking the yanks for help, I think their new anti-missile programme might be a bigger cause of concern!