President Donald Trump mocked Sen. Joe Donnelly (D-Ind.) for agreeing on some border issues on Monday night during a rally in Fort Wayne, Indiana, to stir support for Republican challenger Mike Braun.

“Mike’s opponent is an extreme liberal Democrat named Joe Donnelly,” Trump said.

“He’s gone rogue on the Democrats. He’s gone rogue. Because now he likes Trump a lot. He loves my border policy.”

“They [the caravan migrants] have to come in through a process. They have to come in legally. I don’t know if he said the wall yet, but I suspect he will.”

Related: Mike Braun Has Plan to Shake Up Joe Donnelly, Political Class

Donnelly is fighting to hold onto his seat for another six-year term after first winning it in 2012. He has highlighted his moderate approach and willingness to work with the president throughout the campaign.

Donnelly has sided with the president on a few immigration issues; during a recent debate, he said he would potentially support changes to birthright citizenship.

“All of a sudden he’s talking about what we’re talking about,” the president said Monday night to the Indiana crowd.

“But here’s the problem. There’s one problem,” said Trump. “We’ll have the election tomorrow, and on Wednesday he’ll be totally against us. He’ll never vote for us. He will never ever vote for us. That’s the problem.”

Braun, 64, comes into the race touting his experience as a successful business owner. He has promised to be an ally of the president who will help upset the entrenched political class that he argues his opponent is a part of — he’s constantly accused Donnelly of trying to cozy up with the political elites.

Who do you think would win the Presidency?

By completing the poll, you agree to receive emails from LifeZette, occasional offers from our partners and that you've read and agree to our privacy policy and legal statement.

“They [the Democrats] go back to who they were,” Trump said. “And we’ll never get a vote from Joe Donnelly. When we come in with health care, when we come in with whatever we want, he’ll never [do so]. Because it’s obstruction. Their whole campaign is named ‘resist.’ We don’t want to resist, we want to get things done.”

Republicans see a chance to flip a seat after the president won the state by 19 points during the 2016 presidential election. Trump rallied support for Braun on August 30, and he did the same again last week in a rally that included Vice President Mike Pence and former Indiana Hoosiers Coach Bobby Knight.

Related: Trump Tells Hoosiers He Needs Republican Mike Braun in the Senate

Trump has been holding rally after rally in key battleground states to stir up support for conservative candidates. Before traveling to Indiana on Monday, he held a rally in Cleveland, Ohio, and will soon be headed for Cape Girardeau, Missouri, to cap off a rallied-filled few weeks.

Former President Barack Obama, for his part, rallied for Donnelly in Gary, Indiana, on Sunday.

Donnelly and Braun have remained in a close race throughout the bulk of the midterm election cycle. has kept the race at a toss-up for months.

The Mike Downs Center for Indiana Politics found in a poll last week that Braun has 40 percent support against Donnelly — who has 41 percent.

Watch this video: