Vermont Senator Bernie Sanders has been flat in the presidential polls, has had to shake up his campaign leadership, and he had a heart attack at the start of the month that kept him in the hospital for three nights.

He’s competing to inspire voters with Senator Elizabeth Warren, whose rising poll numbers credibly point straight through the glass ceiling guarding the US presidency. The reasonable move, for young progressive leaders planning for the future, might be to throw in with Warren.

But not everyone is feeling like it’s Warren’s turn. Some pretty big names, it turns out, are feeling… something different.

At a park in Queens, New York, today, Representative Alexandria Ocasio-Cortez is to announce that in 2020, she is once again feeling the Bern. Ocasio-Cortez’s endorsement of Sanders sent shock waves through progressive circles, and raised a host of questions. It also showed the enormous star power of Ocasio-Cortez, who has spent just a year in the House but has already become one of the most influential figures in Democratic politics.

Her move could shake up the race.

Would Ocasio-Cortez – joined in the endorsement by Representative Ilhan Omar, one of the first Muslim women to serve in the US Congress – give the Sanders campaign new snap? Would Warren have to run harder left to compete? And could the endorsements represent a liability in the general election, when it comes time to lure voters who might formerly have backed Donald Trump?

“I think the jury’s still out on how many votes endorsements move,” said Karthik Ganapathy, a progressive political strategist with mvmt communications. “That said, if any one endorsement in the country has the potential to reshape the race, this is the one.”

“The Alexandria Ocasio-Cortez endorsement is a coup for any candidate who received it,” agreed Neil Sroka, communications director of the progressive group Democracy for America. “It’s designed to be a show of strength for Senator Sanders in a moment when many in the national media thought he might have been weakened by the news surrounding his heart incident.”

Facebook Twitter Pinterest Alexandria Ocasio-Cortez on Capitol Hill in Washington Thursday. Photograph: Susan Walsh/AP

Ocasio-Cortez’s starpower on the left is immense. “The extraordinary thing about people who follow her is that a lot of them are young people who aren’t tracking politics very closely,” said Ganapathy. “She’s activated a lot of people.”

For Sanders, the timing seems just right. With only four months to go before voting begins, he sits in third place in most polling of the early voting states of Iowa and New Hampshire, where a victory in 2016 supercharged his campaign. Whatever happens in the early states, Sanders led the pack in third-quarter fundraising and is likely to have the money to run as long as he likes.

But her endorsement strategy is not without risks.

Wizened political observers have questioned whether the timing was right for Ocasio-Cortez, given that her early endorsement could set her up to be a late adopter, if Sanders does not win the nomination, and could detract from the power of her ultimate endorsement, if it came to that.

“It’s interesting that she chose now to blow her political capital,” said Rick Wilson, a Republican strategist. “It goes to show you that just star power alone doesn’t equal good political judgment.”

The early endorsement showed that Ocasio-Cortez was “leading with her values,” Srota countered.

“This is an example, I think, of Alexandria Ocasio-Cortez being true to herself and true to her vision for the future of the country, and to the issues that have guided her from the very beginning of her race for congress back in 2017,” he said.

Facebook Twitter Pinterest Bernie Sanders speaks during a recent rally in Denver. Photograph: David Zalubowski/AP

The endorsement was not quite a foregone conclusion; Ocasio-Cortez had also voiced approval of, and demonstrated some collegial chemistry with, Warren.

Now whatever weight the endorsement has will accrue to Sanders instead. In an analysis of whether the endorsement would move the Democratic primary race, FiveThirtyEight’s Nate Silver pointed out that historically, endorsements have mattered – with the gigantic asterisk of Trump, whom the Republican party at first resisted.

“It’s good news for [Sanders],” Silver wrote, “but it will be better news for him to the extent it presages a more coalition-oriented approach to running a campaign, which includes building alliances with diverse groups of voters and winning endorsements in an effort to expand his coalition.”

Lurking in the background is the question of how Ocasio-Cortez’s support could affect the Democratic nominee’s prospects in the general election. A relatively small pool of polls has indicated that Ocasio-Cortez has a negative favorability rating nationally.

Michael McAdams, national press secretary at National Republican Congressional Committee, said in a direct message that the country is not aligned with Ocasio-Cortez and Sanders.

“AOC’s endorsement of Bernie Sanders confirms the Democratic party stands for a radical socialist agenda including government-run health care, open borders and the redistribution of wealth,” he said.

The statement echoed toxic attacks on Ocasio-Cortez and her colleagues by Trump, attacks the president seems likely to resurface whoever his 2020 election opponent is.

Political strategists on the left said it would be a mistake to craft an agenda around anticipated political attacks, however, as opposed to longstanding policy priorities.

“I don’t think there’s a risk for the Democrats of moving too far left,” said Ganapathy. “Ocasio-Cortez in particular has shown her contempt for a willingness to triangulate.

“It makes perfect sense to me that she would go with Bernie.”