With Donald Trump, three men have now been elected president who were born during a single 66-day period in mid-1946.  

The statistics are boggling — three presidents out of the 841,000 babies born in June, July and August of that first post-war year. In contrast, the 55 million members of the Silent Generation (born between 1925 and 1945) failed to produce a single president.

These three successful graduates of the Electoral College had wildly different backgrounds. George W. Bush (July 6) was born into the WASP governing elite with his grandfather, Prescott Bush, soon to be elected senator from Connecticut. Trump (June 14) was blessed with money from his outer-borough New York City real estate developer father, Fred, but lacked social pedigree. And Bill Clinton (Aug. 19) had nothing beyond a devoted mother, Virginia Kelley.

But all three future presidents came into a world under the shadow of the atomic bomb.

On the day Trump was born, financier Bernard Baruch presented to the fledgling United Nations an American arms-control plan under which the United States would give up its atomic arsenal if other countries would abandon the nuclear option. After the Soviets balked, the United States on July 1 conducted an atom-bomb test (the first since World War II) on tiny Bikini Atoll in the Marshall Islands.

But there were also hints of the coming sexual revolution that summer. The atomic test inspired the French designer Louis Reard to call his explosive, exceptionally skimpy, two-piece bathing suit (unveiled on July 5) the bikini. And it was hard to top the smoldering heat between Lauren Bacall and Humphrey Bogart in “The Big Sleep” released that August.

[Parody: What If Bernie Sanders Actually Endorsed Trump?]

As we grope to understand Trump, our first president with his thumb firmly on the Twitter button, it is easy to neglect the generational factor. Trump seems so impulsive, so instinctual, so nonreflective that it is tempting to regard him as a figure who stands outside history, unaffected by anything other than his own ego needs.

But for someone of Trump’s generation (and, yes, mine) every successful military image is lifted from World War II, which seemed real and immediate for baby boomers growing up in the 1950s. (Fred Trump, unlike George H.W. Bush and Clinton’s father, Bill Blythe Jr., was too old to serve). It is why Trump frequently evokes generals like George Patton and Douglas MacArthur.

For Trump — who ducked the draft like Clinton and, to some extent, Bush — every lost war is Vietnam revisited. Yes, Trump made a crude boast to Howard Stern in 1997 that surviving the sexual merry-go-round disease-free was his “personal Vietnam.” But that doesn’t mean that images of American soldiers coming home in body bags aren’t lodged somewhere in Trump’s brain.

Maybe I’m being too charitable to a president-elect who during the campaign seemed cavalier about whether Japan or Saudi Arabia might develop nuclear weapons. But for someone who came of age during the Cold War — and who undoubtedly participated in nuclear drills as a young student at the private Kew-Forest elementary school — it is difficult to entirely escape a visceral fear that New York could disappear with a mushroom cloud.

As Trump wrestles with the demands of the Secret Service, his mind must flash back to the dominant tragedy of his youth — the 1963 assassination of John F. Kennedy. Long before 9/11, this was the where-were-you-when-you-heard moment for an entire generation.

My guess is that for Trump, JFK rather than Ronald Reagan defines presidential glamor. While Reagan represented dignified old Hollywood, Kennedy defined the Rat-Pack lifestyle with a beautiful wife, dozens of women on the side, adoring crowds and Marilyn Monroe cooing, “Happy Birthday, Mr. President.” On a visceral level, Trump is probably disappointed that Frank Sinatra is unavailable to perform at the Inauguration.  

[Opinion: From Agnew to Trump: Trying to Make TV News Buckle]

Richard Nixon would also loom large in Trump’s memory even if the president-elect didn’t have outside advisers like Paul Manafort and Roger Stone who apprenticed under Tricky Dick. Trump, after all, unapologetically lifted his law-and-order campaign theme (and the use of scary, if bogus, crime statistics) from Nixon’s 1968 playbook.

Nixon also serves as a reminder to Trump that there is only one unforgivable sin in American politics — getting caught. Trump certainly channeled Nixon when he recently told The New York Times, “The law’s totally on my side, meaning, the president can’t have a conflict of interest.”

Trump is likely to be the last president more comfortable with dictating tweets — and everything else — than typing them himself. Only baby boomers who had secretaries early in life (like Trump and Bill Clinton) can still get away with being baffled by the details of 21st century technology.  

(Of course, if Hillary Clinton didn’t have an early feminist’s disdain for secretarial skills, she might have learned how to manage her own emails. Which would have meant that Huma Abedin wouldn’t have had to print them out at home on the computer system she shared with Anthony Weiner. Change that one factor and Hillary, rather than Trump, would be picking a Cabinet as president-elect.)

Trump — like all presidents and not just Reagan — probably has a movie running in his head as he imagines the next four years. The narrative presumably has been molded by every president who touched Trump’s consciousness, maybe dating back to Dwight Eisenhower.

How it will all play out is impossible to guess, although there have been post-election reasons to shudder. But Trump, like Clinton and Bush from the baby-blanket Class of 1946, remains a product and a prisoner of his own living history.

Roll Call columnist Walter Shapiro is a veteran of Politics Daily, USA Today, Time, Newsweek and the Washington Post. His book on his con-man great-uncle was just published: “Hustling Hitler: The Jewish Vaudevillian Who Fooled the Fuhrer.” Follow him on Twitter @MrWalterShapiro.