Republican Calvin Coolidge Was One Of America’s Greatest Presidents.

Given that record, it is hardly surprising that Coolidge was an extremely popular president. He acceded to the White House when Warren Harding died suddenly of a heart attack in 1923, but a year later he was elected president in his own right by a landslide, carrying 35 (of the 48) states and winning 54 percent of the popular vote in a three-way contest with two noted statesmen, Democrat John W. Davis, a diplomat and superlawyer, and Senator Robert La Follette of Wisconsin, the Progressive Party nominee.

Yet for all that, Coolidge was invariably modest and self-effacing, the furthest thing imaginable from a narcissist hungry for applause. “It is difficult for men in high office to avoid the malady of self-delusion,” he wrote. “They are always surrounded by worshipers. They are constantly, and for the most part sincerely, assured of their greatness. They live in an artificial atmosphere of adulation and exaltation which sooner or later impairs their judgment.”

Well-liked and successful, Coolidge could undoubtedly have won reelection to a second full term, but in August 1927 he announced that he did “not choose to run for president in 1928.” The public and the politicos alike were astonished that he would walk away from the pinnacle of power when he could easily have been elected for another four years. No other president in the past 100 years has done so — Lyndon Johnson and Joe Biden withdrew involuntarily — but Coolidge had no qualms about letting go.

”We draw our Presidents from the people,” he later wrote in his exemplary autobiography. “It is a wholesome thing for them to return to the people. I came from them. I wish to be one of them again.”

Coolidge holds another distinction: He was the only governor of Massachusetts to become president of the United States, prevailing where quite a few of his successors failed. It is a tradition for Bay State governors to hang the portrait of a predecessor in their office, and in a column last year I suggested that Governor Maura Healey ought to give that distinction to Coolidge, who occupied the Corner Office in the State House from 1919 to 1921. (Healey ignored my proposal and hung a bare frame on her wall instead.)

But my high opinion of Coolidge, I recently learned to my delight, is shared by a former Massachusetts governor — one I would never have predicted: Michael S. Dukakis.

As a loyal Democrat, a liberal, a first-generation son of Greek immigrants, and a tax-and-spend activist who was elected three times (in four tries) to the Commonwealth’s highest office, Dukakis would appear to have little in common with the quiet, frugal, conservative Yankee who preceded him on Beacon Hill by more than half a century. That’s what Dukakis used to think too, as I learned upon viewing a fine new documentary from the Calvin Coolidge Presidential Foundation.

”I had the conventional opinion about Coolidge,” Dukakis tells an interviewer early in the film. “Then I discovered a totally different Calvin Coolidge from the one I had grown up with.”

Dukakis’s epiphany came in 1998, when he was asked to write a paper on the life of the 30th president for a symposium at the John F. Kennedy Library in Boston. Until then, Dukakis had assumed that the stereotypical dismissal of Coolidge as a mossbacked, do-nothing president was true. But once he embarked on a serious study of Coolidge’s record, he acquired a profoundly different — and far more accurate — understanding of the man. As he later said, it was a revelation.

Dukakis, who for many years was a professor of political science at Northeastern University, has written and spoken several times about his eye-opening research into Coolidge’s career. He contributed an essay, “He Led with Integrity,” to a superb anthology titled “Why Coolidge Matters.” (Among the other contributors are Coolidge biographer Amity Shlaes, civil rights activist Ward Connerly, journalist David Shribman, and historians Melanie Gustafson, Robert Ferrell, and Burton Folsom Jr.)

To his surprise, Dukakis learned that the real Coolidge bore no resemblance to the chilly right-wing ideologue described by New Deal propagandists after his death. Far from it: “This was a man, regardless of his political affiliation and conservative philosophy, who was guided first by what he thought was right for Americans,” wrote Dukakis. “That was also a reflection of his unquestioned integrity and morality. Nobody ever questioned Coolidge’s integrity, including his political opponents.” Is it possible to imagine anyone writing those words today about any president or presidential candidate?

As a loyal lifelong Democrat, Dukakis was fascinated to learn that Massachusetts Democrats in the 1910s and ‘20s “liked and respected Coolidge” and that during his years as a lawmaker on Beacon Hill, “he developed remarkably close relationships with his Irish Democratic colleagues.” Dukakis quotes Jim Timilty, the former Democratic political boss in Roxbury: “Calvin Coolidge can have anything he wants from me. …  Cal’s my kind of guy.”

In his essay, Dukakis understandably applauds those Coolidge policies and attitudes that today might be called liberal or even progressive — his support for a form of universal health care, his pressure on mill owners to increase workers’ wages, his backing of legislation to shorten the work week and establish a minimum wage, and his staunch endorsement of women’s suffrage. The longtime Green Line commuter takes particular pleasure in the realization that he and Coolidge “may be the only two Massachusetts governors who used public transportation regularly.”

But Dukakis’s shrewdest insight about his predecessor is informed by his own years of experience on the campaign trail. Commenting on Coolidge’s unflagging grass-roots organizing and voter turnout efforts, and noting that in the run-up to an election he would make 12 to 15 speeches daily, Dukakis observes: “You don’t campaign the way Coolidge campaigned unless you like people, enjoy the political process, and believe deeply in what you are doing.”

Looking past the stiffly posed black-and-white photographs of his Republican predecessor from a century ago, Dukakis penetrates to the motivation that drove him:

”[Coolidge] was out climbing three-decker apartment buildings in Northampton and ringing the doorbells of those mostly Irish Roman Catholic working class folks who revered him, which led to his election to the City Council. This man was out in the community all the time. You learn a lot on those doorsteps and in those flats.”

Dukakis candidly acknowledges his pleasure in discovering how much there was for him to admire about Coolidge’s life and career. I know what he means. Over the years I have likewise taken a certain satisfaction in exploring the positive qualities of public officials — such as George McGovern, Hubert Humphrey, or Jimmy Carter — whom I formerly only criticized. (This also isn’t my first time finding common ground with Dukakis.)

The former governor from Brookline was born in November 1933, just 10 months after Coolidge died. For most of his long life, and certainly during his 12 years as governor, he would have laughed at the notion that someone of his liberal Democratic convictions would ever perceive in Coolidge the traits of a political paragon. But surprises are always possible for those with open minds. It is good to be reminded of that at any time, but especially in our era, when partisanship has grown toxic and the nation’s politics are fueled by fear and loathing.

Will Americans ever again elevate someone of Coolidge’s sterling character to the White House? In this centennial of his election as president, when the choice on the ballot is between Donald Trump and Kamala Harris, the prospect seems both achingly remote — and devoutly to be wished. May Michael Dukakis — and all of us — be granted time enough to see that wish fulfilled.

This is an excerpt from Arguable, a Globe Opinion newsletter by columnist Jeff Jacoby. Sign up to get Arguable in your inbox each week.