Despite the urging of a legion of Sen. Bernie Sanders’s followers. Sen. Elizabeth Warren did not endorse the Vermont senator in his bid for the White House ahead of the pivotal day of voting on Tuesday. Now, as his rival piles up a large delegate leader, it’s getting harder to see how Sanders could win the Democratic nomination for president.

Since Warren dropped out of the race after a dismal personal showing on Super Tuesday, some thought she might endorse Sanders as her closest ideological ally left in the race. But she has withheld her endorsement from both Sanders and former Vice President Joe Biden, the only other leading candidate in the race.

And according to a new report in the New York Times on Wednesday, it’s unlikely that she’ll endorse anyone before the nomination becomes a foregone conclusion. The report cited concerns about Sanders’s ability to win and his ability to form a coalition — as well as personal discord — as reasons for her to withhold her endorsement.

But the most interesting part of the story was not Warren’s lack of an endorsement and her reasoning, but the reaction Rep. Alexandria Ocasio-Cortez (D-NY.) Ocasio-Cortez endorsed Sanders earlier in the campaign and has been a passionate surrogate on his behalf. Unlike many of the Vermont senator’s fiercest followers, though, she showed no anger or outrage at Warren’s refusal to get on board:

“I always want to see us come together as a progressive wing,” Ms. Ocasio-Cortez said. “I think that’s important and where we draw strength from. But at the same time, I come from the lens of an organizer, and if someone doesn’t do what you want, you don’t blame them — you ask why. And you don’t demand that answer of that person — you reflect. And that reflection is where you can grow.”

It was a remarkably thoughtful and measured answer, and it models an inclusive way forward for the political left in the United States. While it’s easy to get upset when your preferred candidate doesn’t win — and easy to lash out at allies you feel let you down — Ocasio-Cortez shows that it’s better to challenge yourself to do better next time. That’s a constructive way to build a movement, and it’s a sign that she may be one of the people best suited to lead it in the future.

Cody Fenwick is a senior editor at AlterNet. He writes about politics, media and science. Follow him on Twitter @codytfenwick.