Fred Thompson is a fairly good candidate for national office, in a league with, say, John Edwards: one undistinguished term in the Senate, and a regular presence on some crime shows on TV, he looks the part (as everyone points out) and has a consistent conservative take on the issues (can you think of an issue on which his position stands out from the crowd?). My take is not that he's a bad candidate for the GOP nomination, just that he's an average one. So what is the moral of the story? That is that the Thompson bubble reflects the wide-open state of the Republican race. His camp should be worried about the comparisons to Reagan. The last pseudoReagan was George Allen. All you can do is fall off the pedestal; run away from that hype as fast as possible. I also think that the here today, gone tomorrow dynamic in both parties' races reflects the absurdity of trying to pick the president a year and a half before we're going to pick the president. There's too little to lose.
Meanwhile the above-mentioned vacuum might yet help John McCain. A big difference between McCain 2008 and, say, Gore 2004 is that the media loves McCain (while inexplicably loathing Al Gore), and they will run to assist as soon as his campaign shows signs of revival. It is also true that yet more candidates may and probably will emerge. I think Newt Gingrich is going to run, for example. But with this pathologically elongated election season ("season"? This is a lifestyle!), this all rises to approximately the level of baseball trivia at this point.
PS Is "media" here a singular or plural noun? What does Safire say?