While it’s too soon to know if the Republican wave that carried the party to record victories in the 2010 elections will continue or crest in November, a handful of Democratic Senate candidates are posting strong poll numbers in battleground states dominated by the GOP two years ago — giving that party hope that it can hang on to its slim advantage in the chamber.
Incumbent Democrats in Florida, Ohio and Michigan are ahead of Republican challengers in most independent surveys. In Wisconsin’s open Senate race, Rep. Tammy Baldwin, a Democrat, is polling well against a crowded GOP field.
Republicans say it’s too early to pay much attention to polls in those states, especially because senatorial primaries are still months away in most. Also, GOP Senate candidates are polling well against Democrats in several other states.
Still, the early Democratic poll success is welcome news for a party still smarting from an electoral smackdown less than 18 months ago, when it lost control of the House, several Senate seats and gubernatorial posts across the country.
“The head winds in 2010 were very powerful in the Republican direction, and so 2010 should not be taken as indicative of the kinds of results you’re going to get in a normal year,” said Paul A. Beck, a political science professor at Ohio State University.
“Will 2012 be a normal year? I don’t think we know yet.”
A year ago, Sen. Bill Nelson, a moderate Democrat from Florida, where conservative Republicans captured the governor’s mansion and an open U.S. Senate seat in 2010, was considered vulnerable. The race also attracted two high-profile Republican challengers: former Sen. George LeMieux and Rep. Connie Mack.
But since last autumn, Mr. Nelson consistently has led in the polls over Mr. Mack, who is considered the GOP front-runner. The latest survey, a Quinnipiac University poll conducted in late March, showed Mr. Nelson with an 8-percentage-point lead.
President Obama’s improving poll numbers in Florida are credited with boosting Mr. Nelson’s re-election efforts, said Susan MacManus, a longtime political science professor at the University of South Florida.
“Nelson is just tied very closely to Obama in the public’s mind, and as the president does well, Nelson tends to do well,” Ms. MacManus said.
Another Democratic incumbent benefiting from Mr. Obama’s re-election campaign, political analysts say, is Sen. Debbie Stabenow of Michigan, where the administration’s automotive bailout remains popular. She has held steady leads in the polls for months over former Rep. Peter Hoekstra, the GOP front-runner.
“I don’t think she is as personally popular as other senators … we’ve had here in Michigan, but I think that she does a good job to rally the base when it really gets down to election time,” said John A. Clark, chairman of the political science department at Western Michigan University.
Mrs. Stabenow is by no means unbeatable. Her slim advantage of 45 percent to 40 percent over Mr. Hoekstra in a March poll by the Michigan-based Marketing Resource Group was barely outside the survey’s 4-percentage-point margin of error. A month earlier, she had double-digit leads over the Republican in two polls.
“I don’t think polling in the mid-40s is doing well,” said Jennifer E. Duffy, who covers Senate races for the Cook Political Report. “I don’t think she’s the most vulnerable incumbent around. At the same time, her numbers have to be a little concerning.”
In Ohio, Sen. Sherrod Brown, a Democrat, has held double-digit leads over the GOP nominee, state Treasurer Josh Mandel, in most recent polls. Though considered one of the Senate’s most liberal members, the incumbent’s populist persona gives him strong crossover appeal, Mr. Beck said.
“Ohio voters have tended to like those kind of candidates, so I think Brown has in some ways offset his more liberal tendencies that might put him a bit out of the mainstream, at least for Ohio swing voters,” he said.
Many also view Mr. Mandel as a weak candidate who, at 34, lacks the experience and name recognition of Mr. Brown.
In Wisconsin, polls are mixed between Ms. Baldwin and the GOP front-runner, former Gov. Tommy G. Thompson, to fill the seat of retiring Sen. Herb Kohl, a Democrat. Ms. Baldwin holds significant leads over all other GOP candidates, and Democrats say their voters’ enthusiasm in Wisconsin is high this year, fueled by the June recall election of Gov. Scott Walker, a Republican.
Republicans point to Senate races in Montana, Nebraska and North Dakota — seats held by Democrats — where Republican candidates lead in the polls. Senate races in New Mexico, Missouri and Virginia, also Democratic seats, are too close to call.
“From red states to purple states to even blue states, Senate Republicans are on offense and well-positioned in a range of key Senate races across the country,” said Brian Walsh, a spokesman for the National Republican Senatorial Committee, the fundraising arm of Senate Republicans.