Ryan Sager argues that were Fred Thompson to enter the race, Romney’s candidacy would “end almost instantaneously.” While I wouldn’t go quite that far regarding the time frame, I think Sager is largely correct in his general assertion that Romney would be ultimately doomed with Thompson in the race. The primary rationale for Romney’s candidacy has been that with Giuliani and McCain unacceptable to many conservatives and other more conservative candidates unelectable, Romney is the only viable conservative in the race. So far, however, he has remained only potentially viable (he still polls in the single digits) and potentially conservative (his flip-flops have left many doubters on the right). Fred Thompson, on the other hand, possesses a solidly conservativative record as well as the star power derived from his acting career and recent “Law and Order” fame. It’s really hard to see how Romney could overcome that. Personally, I’m skeptical that Thompson will want to leave his comfortable life to subject himself to a grueling presidential race, and, were he to win, spend another four to eight years holding the toughest job on the planet. The fact that his flirtation with running has generated so much buzz is largely a testament to the fact that a lot of conservatives are not happy with the current crop of candidates. For more on Thompson, check out Lisa Fabrizio’s column on our main site.