LEXINGTON, N.C. — Sen. Thom Tillis (R-N.C.) heads into Election Day as an underdog to Democrat Cal Cunningham in a race that could be pivotal to Republicans holding the Senate majority.

Tillis has trailed Cunningham consistently in polls, which show him behind the Democrat among white college graduates, independents, women and suburban voters. Democratic presidential nominee Joe Biden is also in a tight race with President Trump in the state, bolstering Cunningham’s chances.

Republicans had hoped that the race would move in their favor after revelations just last month that Cunningham had an extramarital affair, but that hasn't been reflected in polls.

Democrats need a net gain of three seats and a Biden victory in the presidential race to win the Senate majority, underscoring the importance of the North Carolina race.

Tillis is in trouble, North Carolina political experts say, mainly due to the lack of enthusiasm around his candidacy even among Republicans.

“The thing that has always struck me is a sense of ambivalence among the Republican base,” Michael Bitzer, a Catawba College political scientist, said of the relationship between the state’s voter and Tillis.

“It never felt like he made the sell and has the kind of the die-hard loyalty of Republican voters in particular,” Blitzer said.

Tillis has sought to battle such perceptions by tying himself closely to the president.

He appeared with Trump at a campaign rally in Fayetteville on Monday and later reminded voters of his vote to confirm Justice Amy Coney Barrett to the Supreme Court.

Tillis on Monday during a campaign stop in Lexington, which is Cunningham’s hometown, pledged to work hard for North Carolinians if elected to another term. He also pledged to work hard to win another term.

“I’m going to do everything I can, I won’t leave anything on the table,” Tillis told supporters and volunteers at the Davidson County Republican Party Headquarters.

“I have to work hard because keeping up with the president is hard enough,” he said. “I got to work at least as hard as him and I will, all through the election and for as long as I’m a U.S. senator.”

Tillis told reporters following the event that he is confident he can pull out a win, despite the polls.

Cunningham, a former North Carolina state senator and Iraq War veteran, admitted to his affair last month and has since kept a low profile on the campaign trail. But Tillis has been traveling all over the state, most recently with surrogates like Vice President Mike Pence and former U.S. Ambassador to the United Nations Nikki Haley.

“We’re doing well and I believe we win tomorrow night, I believe President Trump wins, and we save this nation as a result,” Tillis said.

Tillis has sought to use Cunningham’s personal issues against him and said Monday that campaigning on Cunningham’s personal life is “fair game” in this campaign.

“I don’t believe we can trust Cal Cunningham to do what needs to be done at a time of crisis and I also think that his personal behavior is fair game,” he said in Lexington.

“If you run a campaign and spend tens of millions of dollars looking in the camera and saying that truth and honor matter, that’s the foundation of his campaign, and his personal actions have proven definitively that he is neither truthful nor honorable,” Tillis said.

Trump has been accused by a number of women of sexual harassment and assault, however, and Bitzer questioned whether that context has affected how the revelations about Cunningham are reverberating in the state.

He said it seems like voters are “kind of setting the character issue aside, maybe because we’re in a Trumpian world.”

Kerry Haynie, a professor of political science and African American studies at Duke University said “it was surprising” that Cunningham’s popularity didn’t waver after the affair was revealed.

“That’s an indication of how disadvantaged Senator Tillis is and surprisingly as an incumbent,” he said.

But, Steven Greene, a political science professor at North Carolina State University, was more optimistic about Tillis’ pulling out a win on Tuesday.

“I would not be surprised if Thom Tillis hangs on to his seat,” he said. “We’ve seen plenty of polling errors of the size and plenty in recent Senate elections.”