(CNN) Minutes after Ronny Jackson, President Donald Trump's pick to lead the Department of Veterans Affairs, withdrew his nomination under considerable scrutiny, the President had a target to focus his ire: Democratic Sen. Jon Tester of Montana.

Trump, speaking with Fox News, slammed the ranking member of the Senate Veterans' Affairs Committee for leading the charge against Jackson, making it clear to his supporters that Tester's campaign for reelection in 2018 should be a focus after yet another one of his nominations went down.

There should be a "big price to pay in Montana," Trump said of Tester. "I think this is going to cause him a lot of problems in his state."

Tester is one of a handful of Democrats running for reelection in the Senate in a state that the President overwhelming won in 2016. But Tester has cut out his own brand of liberalism in the state and is looking to bank on his authenticity to deliver him another six years in office.

Tester was the face of the Jackson opposition. A document released by Democratic staff on the Senate Veterans Affairs Committee on Wednesday evening alleged that Jackson was "abusive" to his colleagues, loosely handled prescription pain medications and was periodically intoxicated, even once wrecking a government vehicle while drunk.

On Thursday morning, Trump cast Jackson, a rear admiral in the Navy and the current White House physician, as the kind of person the people of Montana want in government, but did not mention the slew of accusations about Jackson's conduct, some of which were unearthed by Tester and his team, that led to his decision to withdraw his nomination.

Jackson denied many of the allegations in his statement -- "The allegations against me are completely false and fabricated," he said -- but announced that he was "regretfully withdrawing my nomination to be Secretary for the Department of Veterans Affairs."

In response to Jackson's withdrawal, Tester thanked the service members who "bravely spoke out over the past week" about Jackson and said it was his "constitutional responsibility to make sure the veterans of this nation get a strong, thoroughly vetted leader who will fight for them."

"The next Secretary must have a commitment to reform a strained health care system and a willingness to stand up to special interests who want to privatize the VA," Tester said. "My sleeves are rolled up and ready to work with Chairman Isakson to vet and confirm a Secretary who is fit to run the VA."

An official with the Tester campaign told CNN after Trump's comments that the idea that the senator was going after Jackson to pick a fight with Trump is laughable and disagreed with the idea that voters in Montana would make Tester pay a "big price" because of his oversight.

"Jon's focus from the beginning is making sure we have strong leadership at the top of the VA so our veterans are taken care of. Jon has worked with the president to get 8 bills signed into law on the VA," the official noted. "That is his goal."

"This isn't political for him, it is about doing right by our veterans," he said.

State auditor Matt Rosendale, one of the top Republicans running for the party's nomination in the Montana Senate race, slammed Tester on Thursday for leading the charge against Jackson.

"Jon Tester took a highly respected man by Presidents Trump, Obama and Bush and personally led the Democrat attack to destroy Ronny Jackson and fight President Trump," Rosendale said in a statement. "He keeps promising Montanans he'll work with the President, but instead he's giving us a load of manure. I'm fed up with these political games from Tester and his blind allegiance to his party bosses and not the people of Montana."

Kevin Gardner, the campaign manager for Troy Downing, another potential Republican challenger to Tester, attacked the Montana senator in a statement, saying, "Clearly, Jon Tester is willing to use rumors and unsubstantiated claims to tear good people down. There will be consequences for Tester in November."

Former state Rep. Russell Fagg, another Republican candidate in the primary, did not immediately respond to a request for comment when asked about Trump's attack on Tester.

In Washington, Tester has often been Trump's sharpest critic among the handful of Democrats up for re-election this year in states Trump won by double-digits in 2016.

He was the only one of those Democrats to vote against ending the government shutdown in January. This week, he also opposed Mike Pompeo's nomination for secretary of state as other red-state Democrats backed Pompeo.

The view from Big Sky Country

In Montana, Tester has struck a different tone. His campaign last month prominently featured Trump in its first 30-second television ad.

Titled "13 Bills," the spot opens with an image of Trump signing legislation and highlights the Tester-sponsored bills that have become law.

"Washington's a mess, but that's not stopping me from getting bills to help Montana signed into law by President Trump," Tester says in the ad.

The ad highlights Tester's distinctive personality despite his status as an influential figure at the top levels of politics, including once chairing the Democratic Senatorial Campaign Committee. The shows him still working on a family farm, wearing a flat-top and telling the story of losing three fingers in a childhood incident.

"I'm out of fingers. But I'm not finished getting things done for Montana," he says in the ad.

Trump, meanwhile, has at times infuriated Washington Republicans by helping clear the field of GOP figures seen as Tester's strongest possible opponents.

He tapped former Rep. Ryan Zinke, who Senate Majority Leader Mitch McConnell had sought to run against Tester, as his Interior secretary.

Then, an unusual confluence of events led another top prospect to pass on the race: Rep. Greg Gianforte was embroiled in controversy stemming from his body-slam of a journalist on the eve of a special election for Zinke's seat. Though Gianforte won, the episode weakened his long-term political prospects. Gianforte was long expected to run for governor in 2020 -- but with him potentially sidelined, Montana attorney general Tim Fox decided to pass on the Senate race, eyeing the governor's office instead.