By Maryam Saleh

Wisconsin’s unusual U.S. Senate race between an incumbent Republican and the former three-term Democratic senator he unseated in 2010 is heating up, but experts say Russ Feingold,  appears almost guaranteed to defeat Ron Johnson, R-Wis.

Besides the significance of such a rebuff to the GOP’s surge in the state, Feingold’s win would bring the Democrats one step closer to winning back control of the Senate.

“I don’t think the Democratic Party here in Wisconsin [is] even worried about this race,” said Kathleen Dolan, professor and chair of the political science department at University of Wisconsin—Milwaukee.

A recent Marquette University poll shows that 46 percent of likely voters support Feingold, while 44 percent support Johnson, and 4 percent stand behind Libertarian candidate Phil Anderson. A statewide poll conducted by the St. Norbert College Strategic Research Institute last week shows that 74 percent of Feingold supporters and 75 percent of Johnson supporters are committed to their respective candidates.

The Democratic challenger has consistently led the polls since the start of the campaign, “which is not a good sign for an incumbent,” Dolan added.

Thirty-four senatorial seats are up for grabs in the Nov. 8 election, and Democrats will need to pick up four or five of the 24 Republican seats to regain a Senate majority. Congress has been under Republican control since the GOP won control of the Senate in the 2014 midterm elections after seizing leadership of the House of Representatives in 2010.

Political pundits predict that Johnson’s Senate seat is one of the seats most likely to flip to the Democrats in three weeks, second only to Republican Mark Kirk’s seat in Illinois. U.S. Sen. Mark Kirk is being challenged by Democratic U.S. Rep. Tammy Duckworth.

Johnson was elected to the U.S. Senate in 2010, at a time that Republicans made enormous gains in Congress after President Barack Obama’s 2008 election. His Senate run was his first run for elective office, having spent decades as a businessman.

Feingold, who is fighting to win back the seat he lost to Johnson six years ago, is a veteran politician with deep roots in Wisconsin politics.

The Democrat served as a Wisconsin state senator for 10 years, representing the state’s 27th District, his home district. Feingold grew up in Janesville, Wis., a blue-collar, middle-class town where many workers lost their jobs as at General Motors factory after the 2008 recession.

After his decade in the state Senate, Feingold was elected to the U.S. Senate in 1992, where he served until January 2011.

Widely considered a progressive, he broke with the party at times. He was the only Democrat to vote against a motion to dismiss Congress’s impeachment case against President Bill Clinton. He was the only senator to vote against the Patriot Act, which gave federal authorities extensive surveillance powers, in 2001. He is a “hard-core liberal,” according to an analysis of his voting record by OnTheIssues, a nonpartisan group that provides information about political candidates.

Johnson has raised $14.8 million to Feingold’s $15.6 million, according to data from OpenSecrets.org, a website that tracks federal campaign contributions. As of July 20, Johnson had spent $9.2 million on his campaign, just slightly more than Feingold’s $8.5 million in expenditures.

In the candidates’ second and final debate at Marquette University Law School in Milwaukee, Wis., on Tuesday night, they turned to personal attacks.

Feingold, who said he was a man of the people, accused Johnson of “stand[ing] with the corporations, the billionaires and the multi-millionaires.” Johnson, in turn, said that Progressives United PAC – a political action committee Feingold formed after losing his Senate seat in 2010 – was a “money-making machine” that spent a significant amount of money on salaries.

Both Feingold and Johnson defended their respective parties’ presidential candidates, and they presented their diametrically opposite views on key issues such as campaign finance, immigration and Supreme Court nominations.

Dolan, who said there was a general consensus that Feingold won the first debate last Friday, said she did not expect Tuesday’s debate to be much different, speaking in an interview a few hours before the event.

The race is closer than it was just three months ago, when a July Marquette University poll showed Feingold with a seven-point advantage.

Still, Feingold’s deep ties to the Wisconsin community give him an edge over the incumbent senator that will likely result in his victory, Dolan suggested.

When Feingold was elected to the U.S. Senate in 1992, he promised to hold an annual town hall meeting in each of Wisconsin’s 72 counties. “People told him he was insane,” the political science professor said, but he kept true to his promise.

Johnson, on the other hand, “went to Washington and really burrowed himself into the party leadership,” instead of focusing on legislation and building a strong constituency relationship in the state, Dolan added.

As a result, many voters are unfamiliar with Johnson, and are less likely to cast a ballot in his favor, she said.

Democratic Presidential Candidate Hillary Clinton’s likely success in Wisconsin, a state that has voted blue in every presidential election since 1988, gives Feingold an added advantage.

“All the projections say that Hillary Clinton will take Wisconsin, and we’ll assume the coattails will take on there,” she added, referring to a phenomenon in which a popular presidential candidate attracts votes for other candidates in his or her party.