Campaign 2006

In the Senate, the Republicans now have a 55-44 advantage, with one Independent who caucuses with the Democrats. Though the odds favor the Republicans retaining control of the Senate—18 Republican-held seats, 15 Democratic-held seats and one open seat are up for reelection—Democrats have a long shot at gaining control. They have a good chance of winning seats in Pennsylvania, Rhode Island, Montana and Ohio. They then have to pick up two additional seats in tougher races in Tennessee, Virginia, Missouri and Arizona to gain a majority.

The House is where the Democrats have the best shot at winning. Democrats must pick up 15 additional seats to win control of the House, where all 435 seats are up for grabs. At present, the composition of the House is 231 Republicans, 201 Democrats, one Independent who caucuses with the Democrats, and two vacancies.

In the upcoming election, only about 40 House seats are in play. Because of recent redistricting, most incumbents have safe seats. If the election were held today, of the 40 [heavily] contested seats, the Democrats would likely pick up 28—mostly in the Northeast and Midwest—and the Republicans 12. That would give the Democrats a razor-thin two-vote majority. But it would be enough to change the dynamics of national politics and put the White House on the defensive.
From Truthdig.org