President Trump tore into Sen. Heidi Heitkamp (D-ND) in her home state Wednesday night, despite the two having a cordial past. Heitkamp showed off some moderate chops and sided with the White House on then-Supreme Court Justice nominee Neil Gorsuch. She also supported Trump's pick for the new secretary of state and CIA director. She has also directed her fellow Democrats not to obstruct Trump's impending SCOTUS nomination after Justice Anthony Kennedy's retirement.

"I was taught that two wrongs don’t make a right," she said. "All senators need to have time to meet and evaluate the body of work of any nominee. Let’s start there.”

But, as the midterm elections approach the president is telling voters that she's all talk. Once the elections are over, she'll go back to voting party line, he told the North Dakota crowd.

"She'll be forced to vote no," Trump said. "Maybe because of this she'll be forced to vote yes. But she will vote no the day after the election, on everything."

When Trump and Heitkamp were still on friendly terms, the former reportedly asked her to change parties. CNN's Jeff Zeleny, who called Heitkamp Trump's once "favorite Democrat," approached the senator this week to ask her if she ever considered becoming a Republican. She said no, telling Zeleny it was a "joke."

"At the end of the day, I'm an FDR Republican," she said, before quickly correcting herself and identifying as an "FDR Democrat."

In Fargo Wednesday night, Trump implored voters to choose Republican Rep. Kevin Cramer as their next senator because Heitkamp has failed to be an "independent vote" as she promised, giving in to Chuck Schumer and Nancy Pelosi far too many times.

"You need a senator who doesn't just talk like they're from North Dakota but votes like they're from North Dakota," Trump said. "That's what you need and that is Kevin Cramer."

Heitkamp is extremely vulnerable, considering Trump won North Dakota with a 36-point buffer in 2016.