When John Bolton was a scholarship student at Owings Mills’ McDonogh School, he learned to stand alone against heavy incoming flak. But he never had to deal with censure like he’s about to absorb.

At upscale McDonogh, this working class son of a fireman out of row-house Southwest Baltimore caught considerable criticism about the war in Vietnam. He loudly supported it, even though he later admitted ducking actual participation in the conflict.

He also led campus cheers (such as they were) for Barry Goldwater’s ill-fated presidential campaign. That was 1964, when Goldwater won six states and lost 44.

For all of this, Bolton earned the wrath of many of his classmates and special mention in the school’s newspaper, where he’d been associate editor. When he stepped down, the paper dropped the phrase “political fanatic” into its farewell to him.

Those were years when Bolton learned to speak his mind, and then dealt with the resultant outcries. He’s good at it. He knows how to fight back.

But Bolton is now caught in a fight between angry Democrats who want him to testify in the Trump impeachment trial and a Republican president who’s about to be quite ticked off.

You want to know what that means?

John Bolton, say hello to Rep. Adam Schiff (D-Calif.), chief antagonist of Trump.            

Against all previous history, and against all odds, and against President Donald Trump, those two are about to have more in common than either of them ever imagined.

Schiff has been catching flak from Trump for the past few years, but never as much as in the last few weeks when he’s been the Democrats’ lead impeachment manager.

Bolton, 71, who was Trump’s national security advisor, now has a book coming out that says Schiff’s telling the truth –- and Trump is not — about the Ukrainian deal at the heart of the current impeachment proceedings.

These two can soon start comparing notes on coping with presidential criticism.

Schiff caught quite a barrage over the weekend, owing to his towering efforts last week to rid the nation of this president.

In response, Trump attacked Schiff on Twitter as “a CORRUPT POLITICIAN and probably a very sick man,” warning, “He has not paid the price, yet, for what he has done to our country.”

Are you paying attention, John Bolton?

What Schiff and the other Democrats have been saying over the past few months, Bolton has now reportedly written for all to see.

The New York Times got access to a Bolton manuscript, not yet published, which says Trump told Bolton in August that he wanted to continue freezing $391 million in military aid to Ukraine until that country investigated Democratic presidential contender Joe Biden and his son, Hunter.

That statement alone casts serious doubt on Trump’s impeachment defense, which says the holdup in aid was separate from any Ukrainian investigation of the former vice president.

“Over dozens of pages,” the Times reported on Sunday, Jan. 26, “Mr. Bolton described how the Ukraine affair unfolded over several months until he departed in September. He described not only the president’s private disparagement of Ukraine but also new details about senior cabinet officials who have publicly tried to sidestep involvement,” including Secretary of State Mike Pompeo.

Times reporters Maggie Haberman and Michael Schmidt wrote, “The book presents an outline of what Mr. Bolton might testify to if he is called as a witness in the Senate impeachment trial.”

Republican senators have been fighting Democrats’ efforts to bring in witnesses. Bolton’s manuscript could conceivably change enough votes to allow that.

In the meantime, what kind of White House flak might Bolton anticipate?

For that, we go back to Trump’s weekend tweets about his chief Democratic antagonist Schiff, and his warning that Schiff “has not paid the price, yet.”

On Sunday’s “Meet the Press,” host Chuck Todd asked Schiff, “Do you take that as a threat?”

“I think it’s intended to be,” said Schiff.

Note to Bolton: You think it was tough at McDonogh?

Brace yourself.

A former Baltimore Sun columnist and WJZ-TV commentator, Michael Olesker is the author of six books. His most recent, “Front Stoops in the Fifties: Baltimore Legends Come of Age,” was reissued in paperback by the Johns Hopkins University Press.