President Obama, speaking at the dedication of George W. Bush’s presidential library Thursday, talked about how no one comes to the Oval Office fully aware of just how tough the job is.

In closing, Obama recounted a story about John F. Kennedy confronting his Soviet counterpart.

“On the flight back from Russia, after negotiating with Nikita Khrushchev at the height of the Cold War,” Obama began, talking about a slip of paper Kennedy had carried in his pocket with a favorite saying on it.

Okay. We recall Kennedy got brutally pounded — and he knew it — by the wily commie. But maybe Kennedy got more disoriented than anyone knew and took a most circuitous route back to Washington?

After all, the only summit Kennedy and Khrushchev had was not in Russia, or anywhere else in what was then the Soviet Union, but rather in Vienna, Austria, in June 1961. (And Kennedy flew home via London, stopping to see Queen Elizabeth, writes historian Michael Beschloss in his book “The Crisis Years: Kennedy and Khrushchev.”)

Okay, so that happened just before Obama was born. But he was nearly 11 when Richard Nixon made his historic trip to Moscow in May 1972, the first time an American president had gone to the Soviet capital.

What was that old song by the great Sam Cooke ? “Don’t know much about history . . . ”

Heads or tails?

Who says your Congress doesn’t legislate solutions to the tough problems of our times?

In addition to, well, the other important things they did last week — like making sure they could fly home on time — Congress debated and passed legislation allowing a commemorative coin to be a few thousandths of an inch smaller than it was supposed to be by law.

We can all rest a little easier now.

The problem began when the U.S. Mint started making commemorative coins marking the Baseball Hall of Fame’s 75th anniversary next year. The bill Congress adopted specifying the design for the coin called for it to be in a dome shape, imprinted with stitches to make it look like a baseball.

But the Mint found that bending coins into that dome shape drew their sides in, making the finished product just a fraction of an inch smaller than the size Congress had stipulated.

This required either a technical solution (i.e., new, expensive equipment) or a legislative one (probably cheaper, since lawmakers and their staff are already on the public dime).

The result: a two-line amendment, “the most technical sort,” according to the bill’s sponsor, Rep. Spencer Bachus (R-Ala.).

But of course, lawmakers used the moment to heap praise on the Baseball Hall of Fame, their hometown teams and the sport in general.

Rep. Terri Sewell (D-Ala.) noted that one of the Hall of Fame’s most popular exhibits is about color-barrier-breaking legend Jackie Robinson. Robinson “served as an inspiration to so many of us in generations to come,” she enthused.

Rep. Chris Gibson (R-N.Y.) even got a bit poetic: “Baseball, America’s pastime, is something that unites us, and I think also something that engenders hope throughout the country, the feeling that we all have in April, the possibility that our team could go all the way and win the World Series. Something, indeed, that unites us.”

At least the bill passed with bipartisan support.

Lasry folds

Marc Lasry, a Manhattan mega-bundler and contributor to President Obama — and before that to Bill Clinton — dropped out of the running last week for that fine ambassadorship in Paris.

Reuters was the first to report that the billionaire hedge-fund head was withdrawing for business reasons. Lasry had never been nominated for the job, though the prospect had been rumored for months, including in this column back in January. Clinton said at a fundraiser last month that Lasry was the pick for the post.

But the New York Post, citing unidentified sources, reported Friday that the withdrawal was the result of his possible ties to an “alleged Russian mob-run poker ring that was laundering money through a Carlyle hotel art gallery.”

“It’s not that he’s committed a crime,” a source told the Post, “but it opens a can of worms” in terms of getting the nomination confirmed.

“Marc plays poker,” a person familiar with the situation told us. And “everyone in those high-stakes games,” including some well-known Hollywood types, “was just as surprised as he was that the organizers had violated the law.” Lasry “has not been contacted by anyone” investigating the matter, we were told.

Off he goes

Secretary of the Air Force Michael Donley announced Friday that he is leaving his job June 21.

Donley has been the service’s top civilian for the past five years and was the acting secretary for seven months before that, making him the longest-serving secretary in Air Force history.

During his tenure, he oversaw a large-scale reduction in Air Force personnel driven in part by budget cuts. “His leadership came during a challenging time for the Air Force, and he helped instill a culture of responsibility, initiative, and professionalism to the service,” Defense Secretary Chuck Hagel said in a statement.

Donley did not immediately announce his future plans, but Hagel said he planned to return to “private life.”

With Emily Heil

The blog: Twitter: @InTheLoopWP.