I agree with Rick Brookhiser's observations on Fred Thompson:

Now that Fred Thompson is officially in the race, it is appropriate to say that he is, on the face of it, by far the weakest potential president of the top tier Republicans...

Fred Thompson came to the offices of National Review some years when he was still in the Senate. I liked him fine. He has done nothing, anywhere, ever. The Hubble Telescope could not find what he has done, because he has not done it.It would be unwise to put such a man in the White House at this moment in history.

But I think he goes a little overboard on Rudy:

Strongest is Giuliani who, alone of all the candidates in both parties, has done something. Two things—saved New York City; and led America for two days six years ago.

Come on--"led America for two days six years ago?!" I didn't realize Rudy temporarily became the nation's commander-in-chief, scrambling F-16 jets and shutting down all commercial flights in the U.S. I find this statement part of the myth surrounding Rudy. How exactly did Rudy lead the nation for two days? I'd like more evidence than emotionally-driven rhetoric.

As for being the only candidate to have done two things, Romney saved the Winter Olympics, saved Massachussetts financially (while saving the taxpayer at the same time), and has numerous accomplishments in the private sector. I think it could be argued that he's the only major candidate with significant accomplishments in both the public and private sectors.