Yes, it had been a good week for Mitt Romney, and that poll showing social conservatives choosing to stick with Rudy GiulianiRudy GiulianiGiuliani hires attorneys who defended Harvey Weinstein The FBI should turn off the FARA faucet Michael Cohen on Giuliani's legal fees: He won't get 'two cents' from Trump MORE despite his rejection of their principles must have had America's Mayor bouncing all over the Big Apple.

But that was then, and this is now. Now that Big Fred is here, the whole game has changed. And if you're a Republican running for president and you're not Fred Thompson, you're running scared. No, he is not the second coming of Ronald Reagan. But beyond his star power, his Southern drawl, his commanding 6-foot-6 frame, is Thompson's ace in the hole: there is nothing wrong with him. Big Fred sprints virtually clean onto a field of negatives — Romney's a Mormon flip-flopper, Rudy's a social liberal protested by 9/11 firefighters and their families wherever he goes with ethically challenged associates like Bernard Kerik, and after six years of courting them, the base just doesn't like poor John McCain. So Thompson may have had an active bachelor career? It hardly stacks up.

What's more, it sounds like Team Thompson is a force to be reckoned with, given their shrewd plan to come out strong from the starting gate — time the dropping of the bomb to ruin the next GOP debate and plot the collection of a boffo war chest before a formal announcement.

This can't be good for the top three who have worked so hard for months.

Thompson will likely dampen Romney's charm and Rudy's swagger with his own.

For his friend McCain, whom Thompson backed for president in 2000 and whose voting record is very similar, it will probably hurt the most. But I imagine there are happy Republicans everywhere. Men have found the tough guy they prayed for, and at least some women are swooning.