It’s semi-official: Al Franken is running for the U.S. Senate from Minnesota. This info, coming from a “senior Democratic official,” retroactively explains the former Upper West Sider’s hasty exit from Air America earlier this week. (He’d already moved himself and his show back to his home state two years ago.) But those that expect the race to be a nice comic diversion from the other 2008 carnage should look elsewhere. Franken is not a novelty candidate — not that that would be a problem in Minnesota, post–Jesse Ventura — and Republicans there, rather than dusting off old Stuart Smalley clips, are already saying unfunny things like “Minnesotans will reject Franken’s divisive, scorched-earth attacks.” He was also a close friend of Minnesota’s liberal, lamented Paul Wellstone, who died in a plane crash in 2002; a Franken candidacy is likely to invoke the specter of the popular senator. At any rate, this should be interesting.