A new round of Senate polls from SurveyUSA, commissioned by Roll Call, show the Republicans in serious trouble for the 2008 Senate races.

In Oregon, Republican incumbent Gordon Smith is ahead but under 50% against two Democrats, leading state House Speaker Jeff Merkley 48%-39%, and leading Democratic activist Steve Novick 45%-39%.

In Minnesota, incumbent Republican Norm Coleman is statistically tied with both his Democratic opponents, with a one-point 46%-45% lead against Al Franken, and a 44%-44% tie against attorney and 2000 Senate candidate Mike Ciresi.

For the open seat in New Mexico, Republican Representatives Steve Pearce and Heath Wilson both trail Democratic Albuquerque Mayor Martin Chávez, with Chávez at 48%-43% against Pearce and 48%-44% against Wilson. This is a turnaround from earlier polls that showed Chávez to be a weak Democratic nominee. Dem Congressman Tom Udall, who is also looking at the race, was not polled.

In the open-seat race in Virginia, former Democratic Governor Mark Warner leads former GOP Governor Jim Gilmore 57%-35%, and leads former Senator George Allen — who has not indicated that he would run — by a 52%-42% margin.

In New Hampshire, incumbent Republican John Sununu trails his 2002 opponent Jeanne Shaheen by a 53%-42% margin.

The Republicans' only bright spot is Maine, where Senator Susan Collins leads Dem Congressman Tom Allen 55%-38%.

Late Update: In another poll result I missed before, Democrats are also ahead in the open-seat race in Colorado, with Dem Congressman Mark Udall leading former Republican Congressman Bob Schaffer 48%-41%.