Two days after the doctor, Ronny L. Jackson, withdrew from consideration for secretary of veterans affairs amid a flurry of reports about his conduct on the job.

Trump made clear he did not intend to let the matter go. In a series of messages on Twitter, the president said the accusations raised by Tester against Jackson were fabricated.

“Tester started throwing out things that he’s heard,” Trump said at a rally with boisterous supporters in Washington Township, Michigan. “Well, I know things about Tester that I could say, too. And if I said them, he’d never be elected again.”

Trump did not elaborate, but it was not the first time he has darkly insinuated that he knew secrets about a political adversary that he threatened to make public. During the Republican presidential primaries in 2016, he warned that he might “spill the beans” on the wife of Sen. Ted Cruz of Texas, one of his rivals for the party nomination, a comment he never explained or followed up on.

The president has for days been sharply criticizing Tester while ignoring Republican resistance to Jackson’s nomination. Tester, the ranking Democratic member of the Senate Committee on Veterans Affairs, took the lead in publicly questioning Jackson’s record, but he had the support of Sen. Johnny Isakson, R-Ga., the chairman of the committee, who signed a joint statement saying the issues should be investigated.

But Tester is from a conservative state that in 2016 supported Trump strongly, giving him 55.6 percent of its votes to 35.4 percent for Hillary Clinton. Even before the flap over Jackson, Trump and the Republicans had hoped to use the power of that 20-point margin to defeat Tester for re-election this fall and defend their narrow 51-seat majority in the Senate.

Tester released a list of accusations this past week against Jackson alleging loose distribution of prescription drugs, a hostile work environment and drunkenness.

The allegations were raised by more than 20 current and former military personnel who had worked with Jackson, whose White House medical unit is run by the military, Tester said, and each of the individual assertions was made by two or more people.

Several of those military officials also described their experiences and concerns about Jackson to reporters, although they spoke on the condition of anonymity because of their status as members of the military.

Jackson called the allegations false and had the support not just of Trump but also of some former aides to President Barack Obama who said they had never observed the alleged behavior while they worked in the White House. But Jackson pulled his nomination Thursday, when it became clear he was unlikely to be confirmed.

“Allegations made by Senator Jon Tester against Admiral/Doctor Ron Jackson are proving false,” Trump wrote on Twitter on Saturday morning. “The Secret Service is unable to confirm (in fact they deny) any of the phony Democrat charges which have absolutely devastated the wonderful Jackson family. Tester should resign.”

He added: “The great people of Montana will not stand for this kind of slander when talking of a great human being. Admiral Jackson is the kind of man that those in Montana would most respect and admire, and now, for no reason whatsoever, his reputation has been shattered. Not fair, Tester!”

Tester fired back a few hours later with a statement noting that Trump had signed eight of the senator’s bills to make the Department of Veterans Affairs more accountable and responsive to veterans. “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.

The White House on Friday sought to refute one of the allegations, that he “got drunk and wrecked a government vehicle,” as Tester’s list put it. A search of government databases turned up no incident that matched that description, the White House said.

Three cases were found involving Jackson and a government vehicle, according to the White House: In one, he was rear-ended. In another, a bus sideswiped a mirror on his car. And in a third, a road rage episode, a driver punched through a window on Jackson’s car.

“Secret Service has just informed me that Senator Jon Tester’s statements on Admiral Jackson are not true,” Trump wrote Saturday afternoon. “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!”

It was the second time in two days that he had drawn a parallel between Jackson’s situation and what he said was his own mistreatment at the hands of the Washington establishment.

White House aides would not comment on whether the president’s remark about the Secret Service was in reference to anything more than the single episode with a car.

Tester said when he released his list that he had not sought out the allegations against Jackson but that military officers had come to the committee with their concerns. He did not pass judgment on their veracity but said that he had a duty to investigate them and wanted to hear Jackson’s response.

A spokeswoman for Isakson said Saturday that he had no comment on the president’s tweets but pointed to the senator’s comment Thursday when he said: “I think everyone has an obligation if they make a charge to release it. And everyone who is charged has a right to have a day in court to be heard.”

Despite Montana’s conservative tilt, Tester has appeared to be in good shape to win re-election, and he has expressed no regret and no public concern about the president’s threats. A former chairman of the Democratic Senatorial Campaign Committee, Tester has raised money at a prodigious rate and had $6.8 million in his campaign account at the end of the last reporting period.

He has drawn a relatively undistinguished group of Republican challengers. Among them, Matt Rosendale, the state auditor, seems most likely to emerge as the nominee.

As it happens, Tester caught a significant break last year thanks to Trump: While national Republicans had settled on Ryan Zinke, then a House member, as the strongest possible challenger for Tester, Trump chose him to be interior secretary, removing him from the race.

But Trump’s easy victory in Tester’s state means his threats cannot be easily dismissed by Democrats. It is likely that Trump will expend much of his energy in the midterm elections on deep-red states with Democratic senators, including West Virginia, North Dakota and, evidently, Montana.

National groups are already spending money in the Montana race, with Americans for Prosperity, the organization funded by conservative billionaires Charles G. and David H. Koch, and the Senate Majority PAC, a Democratic group, beginning new advertising campaigns this month.

This article originally appeared in The New York Times.

PETER BAKER © 2018 The New York Times