After a primary win in New Hampshire, Republican front-runner Mitt Romney “will be very hard to stop” if he takes the upcoming contest in South Carolina, rival Newt Gingrich said Wednesday. And many observers agree with Gingrich.

So, one of the questions for other Republican candidates now is “How can Romney be stopped?” What do you think — specifically, what weakness or vulnerability can opponents seize on as the Jan. 21 Palmetto State primary looms?

Take the poll below and expound on your vote in the comments.