From the moment Hillary Clinton launched her campaign for the presidency, it almost went without saying that President Barack Obama would deliver a soaring address on her behalf at her nominating convention a year and a half later.

What was unclear then, and what remains almost unfathomable today, is how urgent and unusual the subtext of those remarks would have to be. What nobody knew when Clinton stepped down from the State Department is that Obama wouldn’t be striving to unite Democrats with a straightforward appeal to securing his legacy and accomplishments, and fulsome praise for his heir apparent. He did those things, of course. But his purpose Wednesday night in Philadelphia was just as much to make the case for democracy itself so that an authoritarian and fascist like Donald Trump doesn’t become the coda to his presidency.

This was not intended as a pander. Any talented politician can whip their supporters into a frenzy by lying or exaggerating about the opposing party. Republicans, who made “lock her up” the through-line of their convention, and trashed Obama’s America as a degenerating failure, proved as much. To underscore how serious he is about the stakes of this election, Obama was at pains to distinguish Trump from the politicians he expected Clinton’s opponent to be selected from.

Obama had to weigh the esteem of his office and the trust he’s earned over the years against the risk that his remarks would seem manipulative and overblown. He made the right call, and it was as urgent and weighty as any in his presidency.

Consider the contrast between the address Obama gave tonight and the thematic argument of his own convention four years ago. Back then, Democrats were stung and depressed, and anxiously thinking about the cosmic unfairness of the first black president leaving the White House after only one term. They were worried about what would happen to the Affordable Care Act, and the safety net, and to liberalism more generally, if Mitt Romney won. That’s why Bill Clinton’s iconic 2012 speech on Obama’s behalf was all about the ideological contrast between liberalism and conservatism, Obama and Romney, the ACA and vouchers for Medicare beneficiaries. But there was no rhetorical struggle over how to convince voters, without stoking panic or appearing unhinged, that the Republican nominee was an extinction-level threat to American democracy. Because at the end of the day, Romney wasn’t.

The same can’t be said today; Obama and his fellow speakers had to walk precisely that line Wednesday night, and they did it deftly.

Echoing Ben Franklin’s announcement, at the close of the Constitutional Convention in 1787, that the founders had established “a Republic, if you can keep it,” Obama told Democratic delegates, assembled in the same city, that our “democracy works, but we’ve got to want it.”

The election, he warned, “is not just a choice between policies or parties, left and right, [but] whether we stay true to this experiment in self-government.”

This message is beginning to resonate, perhaps not least because Trump is colluding in public with Russia and becoming more and more unglued with each passing night of the convention.

No less a heavy-handed pol than former New York mayor Michael Bloomberg issued a call to band together that won over what, under most circumstances, would’ve been a hostile convention hall.

“We must put [differences] aside for the good of our country and we must unite behind a candidate who can defeat a dangerous demagogue,” he said, pleading with the liberal audience that “as an independent, I am asking you to join with me—not out of party loyalty but out of love of country. “

Vice President Joe Biden’s keynote address didn’t labor long on the struggle between Great Society liberalism and Reaganite conservatism, because that debate is being held in abeyance.

“No major party, no major party nominee in the history of this nation has ever known less or has been less prepared to deal with our national security,” Biden said. “We cannot elect a man who exploits our fears of ISIS and other terrorists, who has no plan whatsoever to make us safer. A man who embraces the tactics of our enemies, torture, religious intolerance. You all know, all the Republicans know.”

The Republicans Biden was referring to serve in Washington; many of them are his friends. And he is depressingly correct. They do know it. And they are supporting Trump anyhow.

If they weren’t, Obama might have been able to float above the ugliness of the election, and give the speech he expected to give just over a year ago: applaud Clinton’s service, affirm her talents, and vouch for the ideas she would fight for  against those the Republican Party offers.

Obama praised Clinton to the heavens Wednesday, of course, and in the same kind of positive terms he would’ve used if Clinton were running against Jeb Bush or Ted Cruz. But at bottom, his closing plea to Democrats is that she’s the only thing standing between our democracy and an unpredictable leap into an authoritarian abyss. “If you’re serious about our democracy, you can’t afford to stay home just because she might not align with you on every issue,” Obama said.

Much more than his legacy depends on that message sinking in, and on motivating the country to do the same thing the last time fascism threatened democracy. “We don’t look to be ruled,” he said. “Anyone who threatens our values, whether fascists or communists or jihadists or homegrown demagogues, will always fail in the end.”