Eight years ago, Hillary Clinton united the Democratic Party behind Barack Obama, helping propel him to the presidency. Four years ago, when Obama was in a close race with Mitt Romney, Bill Clinton defended the president’s record in the most eloquent speech of the 2012 Democratic National Convention. At the time, Obama owed both Clintons a huge debt.

Now, after what will probably turn out to be the best speech of this year’s convention, Obama has paid Clinton back several times over.

Why was the president’s speech so effective? It’s not just that Obama personally vouched for her, though he did that plenty. “There has never been a man or a woman, not me, not Bill, nobody more qualified than Hillary Clinton to serve as president,” he said.

It was more important for Clinton and the country that Obama also defined the stakes in this election, arguing that, despite the anti-Hillary frenzy at last week’s Republican National Convention, it is not just about her. Voters have reason to be proud of how far the country has come from the depths of the financial crisis and its place in the world, he pointed out. But economic disruption, social changes and continuing fears about safety have also helped produce a reaction in the form of Trump that is tearing at the country’s political fabric.

“This is not your typical election,” he said. “It’s not just a choice between parties or policies, the usual debates between left and right. This is a more fundamental choice – about who we are as a people.”

Donald Trump, he said, is “selling the American people short. We’re not a fragile people. We’re not a frightful people. Our power doesn’t come from some self-declared savior promising that he alone can restore order as long as we do things his way. We don’t look to be ruled.” In this way, Obama argued that a vote for Clinton is a vote “to reject cynicism and reject fear and to summon what is best in us,” and it rang true.

As he did so, the president cleverly argued that Republicans could vote for Clinton without turning in their conservative cards. In fact, he said, if they took their principles seriously, they would shun him. “What we heard in Cleveland last week wasn’t particularly Republican – and it sure wasn’t conservative,” he said. “What we heard was a deeply pessimistic vision of a country where we turn against each other and turn away from the rest of the world. There were no serious solutions to pressing problems, just the fanning of resentment, and blame, and anger, and hate.”

Obama was not the only speaker Wednesday night to argue that voters who would normally reject a Democrat must support one this year. Former New York mayor Michael Bloomberg, I, took the stage — to tepid applause from the Democratic crowd — in order to persuade “responsible” independents to vote for Clinton. “No matter what you may think about her politics of her record, Hillary Clinton understands that this is not reality television, this is reality,” he said. Bloomberg went on to give Clinton credit for being “sane” and “competent,” because those are apparently distinguishing characteristics this presidential race.

Once the speeches were through, Clinton joined Obama on stage. The two hugged each other and waved at a roaring crowd for several minutes. The image of the two embracing summed up much of her campaign so far. Whenever Hillary has felt she needed to build credibility on the left, she rhetorically embraced Obama and reminded voters that he trusted her to serve in his cabinet. Wednesday may not be the last time Clinton invokes the president this election year. She may well continue holding onto a relatively popular incumbent in the general election.

Obama has all sorts of reasons to rally hard for Clinton. She may begin returning the president’s recent favors starting next year: Much of his legacy, particularly on climate change and health care, depends on Clinton sustaining his policies from the Oval Office over the next four years. But, as the president said, this election is not just about policy. The stakes are much bigger: Defeating Trump is a moral imperative. And he is telling the country so.

(c) 2016, The Washington Post · Stephen Stromberg