Polls show that the Republican nominee has gained ground in a key Senate race, Wisconsin — and Republicans have put another Senate race, in West Virginia, squarely into play. But strong polling for Democrats in two Pacific Coast states, California and Washington, have somewhat offset these gains, and Republicans are only modestly more likely to take control of the Senate than they were a week ago.
The FiveThirtyEight forecasting model assigns Republicans an 18 percent chance of emerging with at least 51 Senate seats after the Nov. 2 elections; this is up slightly from a 15 percent chance last week. During an average simulation run, Republicans finished with control of 47.6 Senate seats, up from 47.1 last week. The simulation counts possible outcomes in which Senator Lisa Murkowski succeeds in her write-in bid in Alaska as a Republican win.
Republican chances are significantly improved in two states. The first isWisconsin, where three polls show the Republican, Ron Johnson, leading the incumbent Democrat, Russ Feingold, by margins of 6 to 11 points. Prior polling had shown the race to be roughly a tie.
Although Mr. Feingold’s approval ratings have been decent in some surveys and the state has leaned Democratic in recent elections, polls in Wisconsin show a large “enthusiasm gap” favoring Mr. Johnson, a businessman from Oshkosh who has been endorsed by several Tea Party groups. This may be one place where a Tea Party candidate is helping Republicans, as polls had shown other potential Republican candidates in Wisconsin with more tepid numbers. Mr. Johnson is now a 80 percent favorite, according to the model.
The other state to show a big move in Republicans’ favor is West Virginia, where a new survey, from Public Policy Polling, gives the Republican there, John Raese, a 3-point lead. West Virginia remains somewhat underpolled, although three recent surveys from Rasmussen Reports had given the Democrat, Gov. Joe Manchin III, leads of 5 to 7 points, which is enough for the model to still consider him a slight favorite. But Mr. Raese’s chances of winning the state are up to 28 percent, from 10 percent last week.
Over all, the Senate picture is more fluid than a week ago, and somewhat better for Republicans. But were the election held today, they would probably not win the contests in California and Washington, and that would prevent them from accumulating enough seats to take over the Senate (even if they were to win other close races like Illinois, Nevada and West Virginia). Thus, Republicans probably need some additional momentum to claim the Senate, whether in individual states like California or nationally.