WASHINGTON — Donald Trump did Sen. Mark Kirk a big favor on Thursday.

At a closed meeting with Senate Republicans intended to forge unity, Trump, the presumptive GOP presidential nominee, chewed out three senators — including Kirk — for not backing him.

Later in the day, Kirk called Trump an “Eastern, privileged, wealthy bully.”

Locked in a re-election battle with Rep. Tammy Duckworth, D-Ill., and already disavowing Trump, Kirk did not attend the Capitol Hill meeting with the GOP senators. Trump also met with about 200 Republican House members in advance of the Cleveland convention, which kicks off on July 18.

When it comes to fellow Republican Trump, Kirk’s strategy is the more distance he can put between himself and Trump, the better.

On June 7, Kirk yanked his support for Trump, saying in a statement, “After much consideration, I have concluded that Donald Trump has not demonstrated the temperament necessary to assume the greatest office in the world.”

On Thursday we heard a lot more from Kirk — not scripted — about how much he despises Trump.

OPINION

Trump characterized Kirk as a loser at the meeting, according to the Washington Post, which a source confirmed to the Chicago Sun-Times. The Trump campaign disputed the characterizations in the Post article. Trump also declared that he would beat Hillary Clinton in Illinois.

It’s unlikely that both can be true: that Duckworth defeats Kirk while Trump beats Clinton in Illinois.

A major reason Kirk is one of the most vulnerable senators up this November is the expected outpouring of Democratic votes in Illinois. Illinois has been voting for Democratic presidents for the past six elections, since 1992. Trump at the head of the Illinois ticket is seen as suppressing GOP turnout. Clinton is the rising tide expected to lift Duckworth and other down-ticket Illinois Democrats.

If Trump were to win Illinois, it would be because he triggered a huge GOP turnout — which would be a gift for Kirk.

Trump took aim at Kirk, Sen. Ben Sasse, R-Neb., one of the most outspoken Trump critics, and Sen. Jeff Flake, R-Ariz. In a tense exchange, Trump rebuked Flake for not backing him and threatened to attack him. That came after Flake told Trump that he was not comfortable with his comments about Mexicans and his slap at Sen. John McCain, R-Ariz., for being captured in Vietnam, where he was a prison of war for years.

An Associated Press reporter caught up with Kirk in the Capitol to get his thoughts about Trump’s upside-down Illinois predictions: That Trump beats Clinton while Kirk faces defeat.

“I’ve run for election six times in Illinois — really tough race — for Congress and the Senate — and won every race; otherwise I wouldn’t be here,” Kirk replied.

The reporter asked, “Why would he say something like that? I mean, what motivates him to speak that way?”

Kirk warmed to the question.

“It’s the bully platform. He reminds me — we haven’t seen a personality like this too much in the Midwest. Eastern, privileged, wealthy bully. Our bullies are made of better stuff in Illinois. We’re much more practical and polite. We don’t have such personalities like that in the Midwest. We’re nicer than that,” Kirk said.

Trump campaign manager Paul Manafort did not directly address the Kirk situation in his statement about what happened in the meeting.

“Today’s meeting was positive and productive and these characterizations, attributed to unnamed sources, are wholly inaccurate. The conversation was very positive and substantive. The Members were in total agreement with Mr. Trump of the need to unite the Party and work together to win the Presidency and keep a Republican Congress. Mr. Trump was pleased with the discussion and looks forward to working together with the Republican Party leadership towards defeating Hillary Clinton in November.”

In the past months, Kirk has mused that he will write in the name of former CIA Director David Petraeus, the retired general who pleaded guilty to a misdemeanor charge of handling classified information while he was the CIA chief.

On Thursday, Kirk told WGN radio, “I’m gonna write in Petraeus when I vote. And I encourage you, too. I want to see Petraeus get a lot of votes so that just shows that there are thinking people out there that are really concerned about the security of the United States,” Kirk said.

Not leaving that one alone, Democratic Party of Illinois spokesman Sean Savett, said in a statement, “to encourage others to throw away their votes on the disgraced former CIA director who isn’t seeking the office is absurd, and yet another reason it’s hard to take Mark Kirk seriously anymore.”

Trump hits Chicago on Tuesday for a mega-dollar fundraiser.