Four To One For, Four To One Against

Those are the rough odds Nate Silver is assigning the GOP of taking over the House and Senate, respectively here in the final week before Election Day.

The modest decline in the Republicans’ chances today is a result of new polling in two states. The first is Colorado, where two new polls, from Public Policy Polling and SurveyUSA, each show the exact same result, with the Republican, Ken Buck, and the Democrat, Michael Bennet, tied at 47 percent each. Colorado had appeared to slightly favor Mr. Buck for most of the cycle, with his winning chances peaking at 79 percent in our Sept. 30 update. Since then, however, he has endured some decline after a series of minor gaffes, with polls suggesting that Mr. Bennet may have improved his standing among female voters. We now project Colorado’s Senate race to be the closest in the country — slightly closer than others like Nevada or West Virginia. Mr. Buck is now an 0.4-point favorite, according to the model, and his chances of winning are 54 percent.

The other significant move today is in West Virginia, and it is toward the Democrat, Joe Manchin, as a Public Policy Polling survey gives him a 6-point lead over Republican John Raese.

The real movement here is in the Senate, and Nate's position of 52-48 for the Dems is beginning to firm up rather respectably.

Two other important states show slight movement tonight toward the candidate who had already appeared to hold the lead.

In Illinois, a Chicago Tribune poll gives the Republican, Mark Kirk, a 3-point lead over Alexi Giannoulias. This is the fourth consecutive survey to show Mr. Kirk with a lead, and he can now be thought of as a slight favorite. Because of the unusually high number of undecided voters in the state, however, Mr. Giannoulias retains a potential path to victory by turning out the Democratic base.

Finally, in California, a poll for the University of Southern California and the Los Angeles Times gives the Democrat, Barbara Boxer, an 8-point lead over Carly Fiorina. This does not have a tremendous impact on the model, because the poll has consistently shown good numbers for Ms. Boxer and her fellow Democrat, Jerry Brown. But her probability of winning is now up incrementally to 84 percent from 82 percent.

However, Nate's numbers do show the Dems losing 7 seats and about 50 House seats, coming very close to the situation in 1994.  It will all depend on turnout across the country.  The higher the turnout, the better the Dems will do.

We'll see how things go.