Lindsey Graham and Jaime Harrison in dead heat in South Carolina

South Carolina Democrat is either tied or one point behind incumbent Republican in recent polling

Senator Lindsey Graham is mired in the most difficult re-election campaign of his political career, virtually tied with a Democratic opponent, Jaime Harrison, who challenged him at a debate over the weekend over his allegiance to Donald Trump and for going back on his word on several key issues.

The South Carolina Republican has cruised to victory in his three previous Senate races in 2002, 2008 and 2014, winning by an average of roughly 15 percentage points, and never falling below a 13 per cent edge.

But recent polling from CBS News/YouGov and Quinnipiac University showed Mr Graham 1 percentage point ahead of Mr Harrison or tied with him with just five weeks until the 3 November election.

That was before the two candidates appeared at a contentious debate over the weekend, where Mr Harrison lit into the incumbent — known for decades for his bipartisan disposition — for succumbing to partisan politics by allying himself with Mr Trump these last three and a half years.

Case in point: Mr Graham repeatedly sought to tie Mr Harrison to the “radical” wing of the Democratic party that he claims has overtaken it, even though, Joe Biden won the presidential nomination on a more moderate platform than most of his challengers in the primaries earlier this year.

“Your grandparents’ Democratic party is no longer around. The people running the Democratic party today are nuts,” Mr Graham said, accusing them of wanting to “pack” the Supreme Court with liberal judges, provide free health care and open borders to undocumented immigrants, and institute “socialised medicine.”

Both Mr Biden and Mr Harrison have repeatedly and explicitly said they do not support open borders.

“No, we should not decriminalize illegal border crossings. Our goal should be to protect our borders and our national security, while instituting humane policies that reflect our values as a nation of immigrants,” Mr Harrison said at the South Carolina debate on Saturday.

Mr Harrison also admonished Mr Graham for calling Democrats “nuts,” saying it was unproductive for bipartisan discussions that are necessary to cut deals for the American people.

“The first step in terms of working with the other side is not to call the other side nuts,” Mr Harrison said.

“Sometimes people come from different backgrounds and they see the world a little differently, but that doesn’t make them bad because of it.”

Mr Harrison, a former state Democratic party chairman, talked about his good friendship with the former GOP state party chair, Matt Moore, saying they “respected each other” and worked together.

“That’s the foundation for how we get things done,” he said.

After polls in 2016 and 2017 showed Mr Graham with flagging support among registered Republicans in the state, the senator lurched to the right and embraced some of Mr Trump’s hardline rhetoric on immigration and economic policy.

As the chairman of the Senate Judiciary Committee over the last year and a half, he has also fiercely defended the president against accusations he is cozy with Russian President Vladimir Putin. Mr Graham’s committee has been holding public hearings this summer examining the conduct of the Justice Department and FBI officials who headed up the investigations into the ties between Russia and Mr Trump’s 2016 campaign and transition teams.

The strategy worked in the GOP primary earlier this year, with Mr Graham trouncing his three Republican challengers.

But it has left him more vulnerable in the general election to accusations from Mr Harrison that he has gone back on his word on several key issues, such as his newfound support for confirming a Supreme Court justice in a presidential election year.

As chairman of the judiciary panel, Mr Graham will lead confirmation hearings for Supreme Court nominee Amy Coney Barrett beginning on 12 October.

Mr Trump has “has every right to do this,” Mr Graham said on Saturday, regarding the president’s Constitutional authority to appoint justices.

Justice Ruth Bader Ginsburg died just seven weeks out from the 2020 election. Mr Graham opposed Barack Obama’s nomination of Merrick Garland to the Supreme Court in 2016 seven months out from that year’s election.

At the time, he said the following: “I want you to use my words against me. If there is a Republican president in 2016 and a vacancy occurs in the last year of the first term, you can say Lindsey Graham said ‘let’s let the next president, whoever it might be, make that nomination,’ and you could use my words against me and you'd be absolutely right.”

Now, he has said he changed his position because of how Democrats treated Supreme Court Justice Brett Kavanaugh during his confirmation hearing.

That’s political flimflam, Mr Harrison said on Saturday.

“Just be a man about it,” he said, “and stand up and say, ‘You know what? I changed my mind. I’m going to do something else.’ But don’t go back and blame it on somebody else for a flip-flop that you’re making yourself,” the Democrat said.