I have said goodbye to Bernie Sanders before. There was the parting pageantry of the 2016 Democratic convention where Sanders conceded the nomination to Hillary Clinton, closing out a primary season so tight it had given even the most pessimistic of leftists a thrill of hope. As he called for unity against Donald Trump in his farewell, the news network's camera found a crying 22-year-old Bernie delegate in a Robin Hood hat, and the internet tore him apart. Laugh it up, I thought; there will be a next time.

When next time came, the hope died in the spring and Joe Biden trounced him. First they ignore you, then they laugh at you, then they fight you, then you lose.

After Sanders suspended his 2020 campaign, there was no next time to dream about. Sanders is nearly 80 now, and after his heart attack on the campaign trail in 2019, he has no plans to run again. Whoever comes next, it's not going to be Bernie.

Both of us knew that as we spoke on the phone last week, me holed up in insufferable midsummer Washington, D.C., and him enjoying the free New England air.

"When I'm in Washington, I don't go outside," Sanders told me, laughing, "and when I'm in Vermont, I don't go inside. So there you go."

He sounded genuinely upbeat. I wasn't. My first question made that clear: Is it all over?

"No!" he groaned, at typical volume, "I sound like my great-grandmother here. No. Don't have that attitude."

When leftists express despair about Sanders's loss, we are often condescendingly assured that we won the war of ideas, a consolation prize after losing the war for power. Sanders was supposed to have won the war of ideas before, back in 2016, and two years later, a slew of Sanders-backed candidates lost their midterm primaries. If gains made in the realm of ideas don't translate into democratic power, what difference do they make?

Wall Street rallied last week after Biden announced he would run with Sen. Kamala Harris, signaling to markets that they need not worry about dramatic change under a Biden-Harris administration. Seeing as Medicare for All, Sanders' flagship policy and the main focus of his young movement, did not even make it into the Democratic platform this year, that reasoning is probably sound.

"Look, how could it make it when you have a candidate who is strongly opposed to it?" Sanders countered when I brought up the platform's omission of one of his key programs. Does that make him nervous? "Of course it makes me nervous," he said, but "I have a little bit of experience in this. And here's the thing: It takes a two-pronged approach."

The first prong, Sanders explained, is to focus on electing Biden — because the alternative is Trump, whose regime could, in Sanders' view, endanger the progressive cause in ways far more damaging than one led by moderate Democrats. "This is a guy who believes in voter suppression," he said of Trump. "We are fighting for American democracy — for whether we have free elections in this country, or whether you will have an antidemocratic pathological liar running this country. On this issue, there can be not one doubt."

Sanders' movement relies on the idea that transformative change is possible using the normal levers of American governance — which is a point of contention among leftists. But it would be impossible to accomplish without a functional democracy. Whatever Biden may be up to, in Sanders's view, he's at least in favor of that much.

Which isn't to say he's content with the moderate, business-friendly politics Biden favors. And that's where the second prong comes in.

"Now, the day after Biden is elected, we have got to mobilize and organize all over this country to make sure that Biden becomes as progressive a president as is possible, that Democrats control the Senate and the House, and that we can put sufficient pressure on Nancy Pelosi and Chuck Schumer to carry out a progressive agenda."

It's worth mentioning that Sanders has more faith in Biden than many of those among the young left, myself included; many politicians will call one another friends behind the podium only to seethe behind the scenes, but not Sanders. When he says Biden is his friend, he means it: "Obviously, Joe and I have very strong differences of opinion," he said, "but I do know, having talked to him, that he is more than aware of the acute, unprecedented crisis facing this country," a fairly high distinction in the Sandersverse.

Yet Sanders's scheme to nudge the Democrats to the left wasn't too different from the game plan he floated after Clinton accepted the 2016 nomination. I pointed out that things hadn't exactly looked up since then. But Sanders found reason for optimism in, of all things, the pandemic.

"When millions and millions of Americans are losing their health care because they have lost their jobs, when everybody now sees that it is crazy, absolutely absurd to attach your health care benefits to jobs, there's no question in my mind that Medicare for All is winning more and more support." Sanders said.

Still, I couldn't stop brooding over whether increased support would even matter. Weren't health insurers perfectly pleased with the Democratic ticket this time around? Hadn't the Democratic Party itself fought Bernie tooth and nail?

"D'you think?" Sanders joked. And then, soberly: "I'm not worried about how people treated me. That's not really what's important right now," he said. There are more important things, to his mind, than himself; and hasn't he always said so? Not me, us: For as often as Sanders is accused of egomania by his detractors, he isn't calling upon his supporters to avenge him by sitting out; quite the opposite. He still believes change is possible.

One more time, I despaired. How am I to trust that the young people — like myself — who make up the Sanders movement will advance radical policies when they didn't even turn out in sufficient numbers to give him the edge in the primaries? How are we supposed to defeat forces that are just so strong?

If his patience was thinning by then, with all my fretting, it didn't show. Sanders listened, and then delivered a cornerman's pep talk.

"These are the people who run the world," he said. "Of course you're taking on people who are enormously powerful. They own the system. They are the system. They are the system — and it is not easy to make those changes, OK? And it will not happen overnight. And that's why I'm not pessimistic about the future. We are making progress in our fight. All right?"

Sanders cited recent primary victories by some of the most progressive members of the House, including Alexandria Ocasio-Cortez, Rashida Tlaib and Ilhan Omar as examples of left endurance, despite the machinations of powerful, moneyed opponents. There were new primary victories for the left as well: In New York, Jamaal Bowman took out Eliot Engel in a hard-fought race, while Cori Bush pulled off a surprise upset against William Lacy Clay in Missouri. Sanders pointed out that, down the ballot — sometimes way down the ballot — state and local governments are quietly welcoming new members from the Democratic Socialists of America, a major left organizing group that proudly backed Sanders.

There are a few shoots coming up through the snow, and Sanders has no intention of giving up on these tender blooms his movement has nurtured.

"Sometimes people say, you know, you're 78, all that stuff, and you've been doing this for a long time — but should I be quitting now? When you look out and you talk to these beautiful, beautiful young people who want to move this country forward in such a decent, humane way, it really does inspire me," he said. "And to the degree that I have gotten those folks involved in the political process, yeah, I am very proud of that. I don't know that I've ever done anything in my life more important than that."

It was easier this time, saying goodbye.

Elizabeth Bruenig (@ebruenig) is an opinion writer at the New York Times.