Nate Silver has a useful update today on polling of U.S. Senate races. He counts six Democratic pickups as very likely: VA, NM, CO, NH, OR and AK. Three others--MN, NC and GA--are rated as tossups, though like J.P. Green, he thinks Liddy Dole's last-minute religious attack ad on Kay Hagan in NC could well backfire. In the case of GA, Nate figures close to even odds for a rare general election runoff.

KY and MS, while still plausible for Democrats, are not looking quite so good lately. But on the other hand, the one Democratic target going into this cycle, Mary Landrieu of LA, seems completely safe.

If all three toss-ups break Democratic, the party would reach the magical 60 votes in the Senate that would theoretically represent a filibuster-proof majority. But that's only if you count the apostate Joe Lieberman as a Democrat. In reality, of course, a filibuster-proof majority is a vote-by-vote proposition that requires a difficult-to-achieve level of party unity. On the other hand, there are a few Republicans (Snowe, Collins, Specter, and if he survives, perhaps Coleman) who may well be reachable on some key votes.

All in all, it will be a very good election night for Senate Democrats, and we'll really have to wait until January to see how it all shakes out in terms of the ability to govern.