ST. LOUIS — You can make a good argument that Donald Trump won the second presidential debate with Hillary Clinton. You could also argue that no one won. But it’s probably beyond dispute that Trump’s performance will shut down Republican defections from his struggling campaign, at least for now.

Say you were a Republican lawmaker contemplating breaking with Trump. You didn’t do it Saturday, when several GOP officials jumped, because you wanted to see how Trump would do in the debate Sunday night. Now you’ve seen it — a more aggressive, hard-hitting and focused effort than Trump’s losing performance in Debate One — and you’re probably not going to abandon Trump now.