There’s a new Senate Democrat whom President Donald Trump is trying to take down: Sen. Jon Tester of Montana.

Tester is running for reelection in a state Trump won by 20 points in 2016. He’s also in Trump’s crosshairs for his role in the resignation of Rear Adm. Ronny Jackson, Trump’s former White House doctor and his pick to lead the US Department of Veterans Affairs.

As the ranking Democrat on the Senate Veterans’ Affairs Committee, Tester went public about allegations that Jackson was drunk on the job and improperly dispensed medications including Ambien and Percocet to White House staff. Jackson, while denying the allegations, eventually withdrew his name from consideration late last week.

Republican and Democratic senators shared Tester’s concerns about the misconduct allegations and Jackson’s relative lack of management experience, but Trump put the blame on Tester.

Since Jackson dropped out, the president has gone nuclear on the Montana senator. First, Trump called on Tester to resign in a pair of tweets and called the allegations against Jackson “phony” and “slander.” Then he tried to wreak havoc on Tester’s 2018 Senate campaign.

Secret Service has just informed me that Senator Jon Tester’s statements on Admiral Jackson are not true. There were no such findings. A horrible thing that we in D.C. must live with, just like phony Russian Collusion. Tester should lose race in Montana. Very dishonest and sick! — Donald J. Trump (@realDonaldTrump) April 28, 2018

“I know things about Tester I could say, too,” Trump told a cheering Michigan crowd over the weekend. “And if I said them, he’d never be elected again.”

The White House has not elaborated on this, and Sen. Johnny Isakson of Georgia, the Republican chair of the Veterans’ Affairs Committee, has defended Tester’s right to release the information on Jackson.

But Trump’s smearing of Tester has continued into this week, as members of the White House, including legislative affairs director Marc Short, called in to a talk radio show in Montana to slam the senator.

WH Leg Affairs director Marc Short called into a Montana talk show and blasted Tester over Ronny Jackson, accusing him of wanting to "besmirch the character of an admiral in order to score political points against Trump administration" — Igor Bobic (@igorbobic) May 1, 2018

Trump has weighed in on a few Senate races where Democrats are running in states he won in 2016, especially pressuring some Democrats to support Republican tax cuts. But his level of animus toward Tester feels more dogged, and more personal.

A timeline of the Tester/Jackson controversy

Jackson’s problems began on Tuesday last week, when Tester went on CNN and said that about 20 people had approached his committee with allegations that Jackson was routinely drunk on the job and that he dispensed sleep medications, including Ambien, “like they were candy” on overseas trips.

“In the White House, they called him the Candyman,” Tester told CNN’s Anderson Cooper in a Tuesday night interview. In response to the allegations, Tester and Isakson took the step of postponing Jackson’s confirmation hearing until they received more information from the White House.

Then another report surfaced the following day with allegations that Jackson gave a “large supply” of the narcotic Percocet to a White House staff member, wrote himself prescriptions, and once “wrecked a government vehicle” while intoxicated at a Secret Service going-away party (a claim Jackson refuted). The information again came from the Democratic staff on the Veterans’ Affairs Committee, so it had Tester’s fingerprints on it.

Senate Democrats largely avoided speculating about these accusations, more interested in talking about Jackson’s lack of management experience. Tester was the main Democrat out front of the information, and Trump wants to make him pay for that.

Despite Jackson’s obvious drawbacks as a pick to lead the VA (he had managed at most a staff of 70 and would have jumped to overseeing hundreds of thousands of employees), Trump seemed to really like his White House doctor.

Jackson recently gave the president a physical and delivered a glowing assessment of Trump’s health to the Washington press corps. Trump has repeatedly called Jackson a “great man” and complained about what the allegations have done to him and his family. Trump is a man who prizes loyalty, and he seems to be loyal to Jackson.

Therefore, Trump is set on bringing down the man who brought down his VA pick.

Will this actually hurt Tester in 2018?

It’s way too early to tell whether Trump’s railing against Tester will actually hurt the senator in his 2018 bid for reelection, but it could become a huge flashpoint in the Senate race.

Montana is home to about 100,000 veterans — about 9.4 percent of the state’s overall population. Tester has long prided himself as a champion for veterans and claims he acted in the best interest of veterans throughout the Jackson fracas.

“It’s my duty to make sure Montana veterans get what they need and have earned, and I’ll never stop fighting for them as their senator,” he said in a statement to CNN responding to Trump’s weekend attacks.

Despite being on the list of most embattled Senate Democrats in 2018, it looks like Tester is faring better than some of his colleagues like Claire McCaskill of Missouri, Joe Manchin of West Virginia, and Heidi Heitkamp of North Dakota. Tester’s most well-known Republican challenger is state auditor and former state Sen. Matt Rosendale.

Tester is fairly well-liked in the state; he has a 56 percent approval rating, and Rosendale has failed to generate a lot of excitement among Republicans so far. The nonpartisan Cook Political Report rates the race Likely Democrat, which is good news for Tester. And he has a sizable chunk of campaign cash and is already fundraising more in the wake of Trump’s attacks.

Trump won the state by 20 points in 2016, but he now has a 52 percent approval rating in Montana. He’s going after Tester, but it remains to be seen whether he will lose steam — or whether his attacks on Tester will stick.