Michael Barone combs through this year's Senate races and predicts a Democratic floor of 56 seats, with five toss-up races in Republican-held seats: Kentucky, Minnesota, Oregon, North Carolina, and Georgia.

What's my bottom line? If I had to bet $1,000 on each of these races, I would bet on [Oregon's Gordon] Smith and [North Carolina's Elizabeth] Dole to lose, and [Minnesota's Norm] Coleman, [Georgia's Saxby] Chambliss, and [Kentucky's Mitch] McConnell to win. That, assuming Sununu doesn't somehow pull it out, would leave the Democrats with 58 seats. (But I could easily be wrong on any or all of these races, and I reserve the right to change my prediction before Tuesday.) Fifty-eight Democrats would be enough to stop filibusters if they can get a couple of Republicans (and not drop any Democrats) on an issue, but not enough to run the table.

The thing is they probably would be able to pull in enough Republicans to pass the Obama agenda. Fifty-eight seats would be the biggest majority any party has had in 30 years, and that was a Democratic conference that included a lot of conservatives. In 2010 there will be 18 Republican seats on the ballot, a reflection of the great year that the party had in 2004. Sen. Arlen Specter is one of them, so not only is he pro-choice and pro-Employee Free Choice Act, he'll be girding for an epic battle in a state that's getting more and more Democratic. Sen. David "Ask me about my sex with prostitutes" Vitter is another one. Sen. Judd Gregg of New Hampshire has survived a number of tight contests, but his state is poised for the biggest Democratic landslide since 1964.

At the same time... it's not hard to imagine an unpopular Democratic presidency inspiring a bunch of strong Republicans to run to take back a majority. But where? Maybe they can Daschleize Harry Reid in Nevada. Maybe Schwarzenegger will run in California, Huckabee in Arkansas, and Gov. Hoeven in North Dakota. Maybe 86-year old Daniel Inuoye retires in Hawaii and Gov. Linda Lingle, a Republican, runs to replace him. Hey, Republicans picked up eight seats in 1994. Democrats picked up six in 2006.

The question is whether Obama is more like Bill Clinton or like Ronald Reagan. Clinton stumbled into the culture wars, broke a tax cut pledge, and botched health care reform, and strategy-minded Republicans could see the path back to power. Reagan presided over a terrible recession and threatened Medicare cuts, yet his party held the line in the Senate in 1982 (while losing seats in the House.) Obama's people must have studied these two examples and know that getting the big accomplishments out of the way first (like Reagan's tax cuts, not like Clinton and Don't Ask, Don't Tell) and charming the hell out of the country can mitigate losses even if voters grow sour by the midterms.

We'll get a tiny, confusing sense of how this will play out if the Georgia Senate race isn't decisive. Libertarian Alan Buckley is polling well enough in Georgia that neither the Democrat nor Republican could crack 50 percent of the vote and the state might go to a runoff.