Why is John F. Kennedy still so popular?

John F. Kennedy had his flaws and made mistakes during his presidency. But he perfectly embodied a bygone era of boundless American optimism.

Fifty years after his assassination in Dallas, John F. Kennedy remains the most admired US president of the post-World War II era. Why is he still so popular after all these years?

He didn’t do much in terms of passing legislation. The big civil rights and tax-cut bills associated with his name were actually pushed through Congress by President Lyndon B. Johnson. Partly that was because Kennedy did not actually have that much time in the Oval Office, serving as president only a thousand days.

He’s remembered as the hero of the Cuban Missile Crisis, resisting the advice of many security officials to destroy the Soviet launchers with military force. But Kennedy’s approval of the Bay of Pigs invasion at the beginning of his term was a mistake that might have led Cuban leader Fidel Castro to accept those launchers in the first place. And Kennedy escalated US involvement in Vietnam, increasing the number of US advisers in the country from a few hundred to 16,000 while opening the spigots of military and political aid.

Then there’s his womanizing. In recent decades, credible reports of his many mistresses have cast his personal life in a far different light.

But despite all this, in Gallup polls Americans have named Kennedy as the most outstanding US president of the modern age ever since the firm first asked that question in 1990.

In the latest Gallup poll, released this month, nearly three-quarters of respondents said Kennedy will go down in history as an outstanding or above-average US chief executive.

“This is the highest retrospective rating given to any of the 11 presidents who have held office since Dwight Eisenhower,” write Gallup’s Andrew Dugan and Frank Newport.

Other pollsters have produced similar results. A new Hart Research survey conducted for the University of Virginia’s Center for Politics found respondents rated JFK as the best president of those elected since 1950.

On a scale of 1 to 10, respondents rated Kennedy as a 7.6, on the mean. Ronald Reagan was second at 6.9 and Dwight Eisenhower third at 6.8.

Well, for one thing, Kennedy’s reputation started off high. He’s not just popular in retrospect. He was extraordinarily popular while in office.

His average job approval rating from 1960 through 1963 was 70 percent, according to Gallup. That’s 5 points higher than the number for Kennedy’s predecessor, Eisenhower, and much higher than the average approval for all JFK’s successors.

Second, Kennedy’s image of youth and energy has echoed down the years. His charisma comes through, even in black-and-white photos. He was, and remains, a president Americans believe stood for real hope and change.

The Hart survey asked respondents to write a brief impression or feeling about JFK’s most significant attribute. “A great man, a good family, youthful, energetic, relatable” was the most common response.

Asked to pick from a list of words that symbolized the mood of the country in 1963, a plurality of 37 percent of voters today pick “changing,” according to the Hart results. Thirty-six percent picked “young/youthful.”

Third, the revelations about women do not appear to have affected his reputation as president. That’s implicit in his continued popularity among voters. It’s explicit in Hart findings. The firm asked voters if reports of Kennedy’s extramarital relationships had affected their view of his presidency. Forty-four percent said it made them feel less of him as a person, but not as a president. Thirty-six percent said it made no difference either way.

Only 17 percent of adults said it made them view JFK in a more negative light on both personal and political grounds.

Finally, Kennedy’s untimely end may play a part in his popularity. He’s become enshrined as a martyr, particularly in Democratic households. But William McKinley was another popular, energetic president cut down by an assassin’s bullet. He faded from the popular mind in a way JFK has not.

Maybe it’s because Kennedy, even now, so embodies that era's palpable sense of freshness and promise. The youngest man elected to the presidency, Kennedy smiles brightly in those photos from Dallas from before his fateful turn near the Texas School Book Depository. On the morning of Nov. 22, 1963, Americans were upbeat about him and about the nation, points out Andrew Kohut, founding director of the Pew Research Center. Fully 82 percent thought America’s power would increase in 1963. Sixty-four percent said business conditions were good.

“The mood of America then had few parallels with the modern era,” writes Mr. Kohut.

Today, we yearn for that time before Lee Harvey Oswald’s rifle shots took America’s innocence. Some of that is baby boomer nostalgia for their past youth. But polls show those too young to remember JFK’s assassination view him almost as positively as do their elders.

“We will always see Jack and Jackie in the majestic black presidential limousine, smiling, waving, bathed in adulation and glorious sunshine,” concludes Larry Sabato, a University of Virginia political scientist and author of the “Kennedy Half Century: The Presidency, Assassination, and Lasting Legacy of John F. Kennedy.”