I've written about experience before, and Kevin Drum's argument is similar to what I believe: as it's used now, experience seems to mean little more than how much time one has spent in the public eye as a major figure.
This being said, I just don't think experience matters a whole lot to voters. Think about it: in the last four elections, the major party candidate with more government experience lost. Sure, two of those times the winner actually had more experience as president, but my point is that this seems to often be a losing argument. Nixon lost on it in 1960, despite running on Ike's record and popularity. Carter lost on it in 1980, and that was one of the few points in his favor. Bush 41 lost on it in 1992. And Gore's loss in 2000 came despite a concerted effort to paint George Bush as inexperienced. Sure, other campaigns have utilized experience to one degree or another, but these are the major ones that I can recall.
It seems like there are two different trends here: in 1960 and 2000, the incumbent party was coming off of a reasonably popular two-term presidency and both times ran a candidate promising to continue the status quo and was simply out-gunned. In 1980 and 1992, we were in the midst of two unpopular administrations, in the midst of poor economies that the respective chief executives seemed incapable of fixing, and both times the opposition candidates were charismatic and talented. To the extent that McCain seems intent on adopting Bush conservatism in order to appeal to his "base", it seems like his campaign is the prototypical example of the second trend--an experience candidate swimming against the increasingly powerful waves of change running through the country. And modern history does not seem to be too kind to such candidates.
Generally, I tend to loathe historical trends, but I think the pattern is pretty inescapable. In any event, after getting his base locked down, I fully expect McCain to start running as a Sarkozy-style change and continuity-style presidential candidate.
