Now that's rich
To take this argument seriously, you'll need to forget that in 2000, Republicans nominated George W. Bush, whose time in elective office consisted entirely of a term and a half as perhaps the nation's most powerless governor. You'll also need to ignore the examples of Abraham Lincoln and Dwight D. Eisenhower, who did all right despite their paucity of time as elected officials.
Experience is important, of course, but it's tough to argue that candidates' raw amount of experience, in and of itself, always should be the decisive factor in who's better suited for a job. Vice President Cheney has more governmental experience than almost any major-party contender, but to say the least, I don't see people rallying in the streets demanding that he run in 2008.