The last time I’d toured the Truman Library, as a young graduate student in history at the University of Missouri, the guide was the library’s namesake. Always dapper — after all, he’d been a haberdasher in another failed career — Harry Truman was, well, Trumanesque. He was crisp as the white, pointed handkerchief in the breast pocket of his single-breasted dark blue suit.

With his natty bow tie and eyeglasses always in place, he could have stepped out of a political cartoon. He was folksy without being folksy, his style no-style, but just plain Missouri show-me. His manner might have been practiced, his best lines well rehearsed, but the whole effect seemed natural to the man and the place — right here. Independence.

While aware of the impression he was leaving — he was, after all, a politician of some note — the man had no airs, certainly not intellectual ones. He’d been there, done that, and didn’t need to philosophize about it.

He was an earnest student of history — the old-fashioned kind with heroes and villains, right and wrong. None of this Toynbeean murk for him. He knew what he knew, the rest he would learn — if he thought it worth learning.

Truman never did have much patience with the pretentious. At a particularly low point in his presidency, his party having just lost the midterm elections, a distinguished senator from Arkansas on the Senate Foreign Relations Committee suggested that he resign the presidency in the best British tradition. Much like a prime minister leaving office after a vote of no confidence.

Harry Truman didn’t think much of that idea. And as for the senator who’d come up with it, he dismissed the Honorable William Fulbright as someone who’d been “educated above his intelligence.” And that was one of his milder descriptions of the gentleman from Arkansas.

About the only feature I remember from my earlier visit to the Truman Library was a huge Persian carpet that had been suspended from the balcony. We’d pass it more than once during our brief tour, and each time Mr. Truman would say, “Yeah, that’s a rug the Shah of Iran gave me.”

The rug isn’t there any more. The shah is out of fashion and the rug is no longer in sight. Political correctness must have overtaken even this monument to Give ‘Em Hell Harry.

A captain of artillery during World War I, he may have acquired a certain familiarity with the stock profanities, but the elementary decency of the man shone through. He tended to rise above his surroundings. Maybe that’s how he could be in Kansas City’s old Pendergast machine but not of it.

By the time he was showing students around his library in the late 1950s, Harry Truman was just another failed president. Communism, corruption, and Korea had done him in, to quote the GOP slogan in 1952, and he’d left the White House with poll ratings somewhere down in the 20s.

It was left to General Eisenhower, his successor in the White House, to demonstrate that decency could also prove successful politics.

As in 1948, Truman would eventually stage a comeback, this time in history’s ratings — not that he ever had any doubt he would. Or doubts about much of anything else, including his decision to drop the bomb on the Japanese. He didn’t believe in wasting time on remorse.

Now it was almost half a century later and we were being addressed by a Truman impersonator. He looked the part in his rimless eyeglasses, now back in fashion after half a century.

The suit was a 1940ish double-breasted model, but the pointed white handkerchief in the breast pocket was still crisp. When he was leaving the White House, someone asked Harry Truman what he would do when he got back to Missouri. “Unpack,” he said.

As a private citizen — a promotion, he would say — Mr. Truman was deluged with corporate offers to head up this or that new company, or at least lend it his name, or maybe start raking in fees for personal appearances. He refused, saying he didn’t believe the presidency should be exploited that way. As I said, it was a different time.

The Truman Library was an interesting place even in the 1950s, and it has been much improved since. It’s well worth a visit. Particularly in contrast to presidential libraries that are newer and still intent on canonizing their subjects. Political passions take a while to ebb.

In contrast with the Clinton presidential library in Little Rock, the more objective presentation of history here refreshes. For example, the arguments for and against dropping the bomb on Hiroshima — and Nagasaki, too, lest we forget — are neatly and fairly summarized.

An exhibit on the tumultuous beginnings of the Cold War in the Truman administration sums up the Hiss-Chambers Case — our own bitterly divisive Dreyfus Affair — in the fairest terms. The text alongside Alger Hiss’ picture is so balanced it’s hard to imagine its being written when the debate over Hiss’ loyalty still raged:

“Not all the shocks of 1949 and 1950 occurred overseas. In January 1950, the explosive case of Alger Hiss also grabbed headlines. Hiss was a former State Department official accused of spying.

“In 1948, Whittaker Chambers, a former editor at Time magazine, had told a congressional committee that he and Hiss had once been Soviet agents. Hiss denied the charge, but his case became a national sensation.

“Because the statute of limitations on espionage had passed, Hiss was tried for perjury. His first trial ended with a hung jury. At a second trial, he was found guilty. The verdict, coming at a time of widened public fears about Communism, fed a growing hysteria about spies and traitors.

“Controversy over Hiss’s conviction finally faded during the 1990s, when strong evidence that he had indeed been a spy emerged from Soviet archives and U.S. Intelligence files.”

The passage of time and fading of passions allows a presidential museum to sum up even the most controversial aspects of an administration with evenhanded dispatch. Compare the Truman Library’s verdict on the Hiss-Chambers affair to the Clinton Library’s exhibit on l’affaire Lewinsky. If you can find it.