In ten Republican presidential debates, Mitt Romney has been challenged, criticized, sometimes ridiculed — but never smacked down. That streak came to an end Tuesday night at the 11th GOP debate, a session devoted exclusively to national security issues, when Romney tangled with libertarian candidate Ron Paul over the frenzy of budget-cutting proposals in Washington.

It happened after Paul was asked a question about foreign aid, which, to no one’s surprise, he opposes. “I think the aid is all worthless,” Paul said.  “This whole idea of talking about the endless wars and the endless foreign aid, it seems like nobody cares about the budget. I mean, we’re in big trouble, and nobody wants to cut anything.”