You mean he wasn't a Thompson supporter already?
But we can't just go by our gut. Let's compare the main attributes of Fred Thompson versus the other candidates:(via)
Fred Thompson: Teh Awesome
Other Candidates: Teh Suck
I should note, though, that the most important factor in IMAO endorsing Fred Thompson is that I already have an awesome t-shirt designed for him which will pretty much go to waste if he isn't the nominee. And it's not like I can just move that slogan to whoever the Republican nominee is, because, come on, do you think a tough slogan like that is going to work with Romney or hyuk-hyuk-Huckabee? No. Fred Thompson is the only Republican with the awesomeness to pull that off.