More than a half century ago, after he defeated Richard M. Nixon in one of the closest presidential races of all time, John F. Kennedy was persuaded to fly from his Palm Beach retreat to the vice president’s Key Biscayne redoubt as a symbol of national unity. The two men were far closer than Barack Obama and Mitt Romney are, but still there was some awkwardness in the gesture, which had been cooked up by former Ambassador Joseph P. Kennedy and former President Herbert Hoover.

The two, both Navy men who went to Congress in 1946, met amid palm trees and flashing photographers’ lights, and perhaps no one noticed then what is so obvious now from the aging footage of the event, that the victor, whose breakthrough came in the first presidential debate earlier that autumn, wore a dark suit and that the vanquished wore a gray suit, tantalizingly like the one that allowed him to fade into the background so disastrously at the WBBM-TV studio in Chicago.

The president-elect began with a question that nagged at his mind, asking his opponent: “How the hell did you carry Ohio?”

Perhaps in a few days Obama and Romney will meet, for in truth the nation needs a robust symbol of unity far more in 2012, when the two candidates differed on so much and assembled coalitions that opposed each other with such anger and distrust, than it did in 1960. Kennedy and Nixon were — despite the folklore that now portrays the contest as a titanic struggle between bitter rivals and competing worldviews — more alike than different.

The campaign just completed will be remembered for the struggle for Ohio, but also for its intensity, its nastiness, its price tag. The two combatants fought fiercely. They obscured their own records and distorted their rivals’. Their allies portrayed their opponents as monsters in a Manichaean struggle of good versus evil. In that, as in so much else they said, they were wrong.

Tuesday — “America’s choosing day,” in Walt Whitman’s characterization of the election of 1884 — the nation whispered that it wanted to continue on the Obama path, but shouted that it wanted to do so with a different pace, in a different tone, with a different result.

Now Obama is no longer the man of hope and change, but a scarred and realistic president whose people gave him a second term and a second chance in the hope he might change.

Now Obama — no longer the charmed prophet floating above the political landscape — has a new beginning. But he will have difficulty claiming a mandate, and the animating question of American politics now is what he will do with his new beginning and what he must do to govern with anything approaching effectiveness.

The heavy turnout, perhaps a result of one of the many unintended consequences of the Citizens United decision, is almost certainly an indication of the urgency and intensity Americans feel about the problems that Obama didn’t tackle or solve in his first chance: Slow economic growth. Stubbornly high unemployment. Terrifying consequences of the imminent fiscal cliff, of the unaddressed entitlement crisis, and of the smoldering danger that is apparent in every household but reported in almost no news outlet — insufficient pensions and savings to carry hard-working, middle-class Americans into retirement.

If people were waiting 45 minutes to vote in Richland Township in southwestern Pennsylvania, and as much as twice as long in parts of Virginia, it very likely is because they have waited for years for politicians to address these problems.

Obama’s victory was muted compared with his 2008 triumph.

The American people gave Obama a new start, but in awarding him a second term, they changed the terms of engagement. Not so much four more years, they seemed to say, as four different years.

In the last day of his last campaign, Obama returned to Iowa, where his unlikely rise to power began with an astonishing caucus victory in the winter of 2008, and there he spoke of his “movement for change.” Hours later, the voters’ verdict indicated that Americans do want change, just as they did in 2008, but also a change in the way the president conducts business. The margin of victory this time, smaller than it was four years ago, is a signal that its chief executive’s performance was acceptable, but only barely so.

Two months after that remarkable 1960 meeting in Key Biscayne, newly inaugurated President Kennedy, seemingly awed by the challenges he faced, stood before both houses of Congress and delivered a sobering State of the Union message.

“We cannot afford to waste idle hours and empty plants while awaiting the end of the recession,” the 35th president said. “We must show the world what a free economy can do — to reduce unemployment, to put unused capacity to work, to spur new productivity, and to foster higher economic growth within a range of sound fiscal policies and relative price stability.”

So, too must Barack Obama’s America.

Four years ago it seemed as if Obama had begun a new era of progressivism, fueled by a new generation of Americans who had turned away from conservatism. This morning that seems far less certain.

Four years ago it seemed as if Obama were asking big questions and positing big answers. This morning, even in the glow of his re-election, he seems the prisoner of those big questions and chary of big answers. The question now is how Obama, flush with fresh victory but sobered by his challenge, will change, and whether Washington can change with him.