(CNN) Democratic presidential candidates are vying to be seen as Alexandria Ocasio-Cortez's ally -- even if they don't ultimately win her endorsement.

Massachusetts Sen. Elizabeth Warren showcased her alliance with the freshman lawmaker from the Bronx on Thursday. The two penned a five-page letter -- and released a three-minute video explaining it -- pressing Treasury Secretary Steven Mnuchin over his work on Sears' board while his roommate from Yale gutted the department-store giant on its way to bankruptcy.

Still six years short of the Constitution's minimum age requirement to be president herself, Ocasio-Cortez's massive social media following and ability to generate news headlines has made her a key player in the race for the 2020 Democratic presidential nomination.

With progressives looking to stand out in the crowded field of more than 20 candidates, some Democrats believe that no endorsement -- other than the Obamas -- would be more potent in than one from Ocasio-Cortez.

Her closest links are to Vermont Sen. Bernie Sanders, for whom she and many of her aides and the activists in her orbit worked in 2016, and to Warren, who had lunch with Ocasio-Cortez and wrote the Time essay when the magazine included her on its list of 2019's most influential people. The two also recorded a short video criticizing the ending of HBO's "Game of Thrones" this week.

"What I would like to see in a presidential candidate is one that has a coherent world view and logic from which all these policy proposals are coming forward. I think Sen. Sanders has that. I also think Sen. Warren has that," Ocasio-Cortez said earlier this month.

She said she doesn't expect to endorse a candidate "for a while."

"I think she just wants to let this process play out a whole lot more than it already has. She's still watching and making up her mind," Ocasio-Cortez spokesman Corbin Trent said Thursday. "She's made it very clear whom she's not supportive of and whom she is. And it's about their policies, period."

Even if an endorsement isn't coming soon, Democratic presidential contenders who are courting the party's progressive voters are finding value in being seen as Ocasio-Cortez's ally.

Warren, for example, was the subject of a Washington Post report Thursday that she charged as much as $675 an hour while working on legal matters during her time as a Harvard Law professor. Ocasio-Cortez's sarcastic mockery of the story on Twitter found its way into other news outlets' coverage, possibly helping minimize its potential damage to Warren's campaign.

"She was able to, on her very loud mic of millions of followers on Twitter, call it out in a way that I think shaped the debate. That's not just about having an endorsement," progressive Democratic strategist Rebecca Katz said.

Rather than endorsing a candidate, Ocasio-Cortez has seized on an opening in the early stages of the presidential race to shape the platforms of multiple candidates in the 2020 race as their campaigns piece policy proposals together.

California Sen. Kamala Harris is expected to join one of Ocasio-Cortez's policy fights after Memorial Day. She'll introduce the Senate version of the Fair Chance at Housing Act, which would roll back "one-strike" policies that can lead to families' eviction from public housing if any member of the household is involved in even minor criminal activity.

There are no plans currently in place for the two to record a video or hold a joint event pushing it, sources familiar with the matter said.

Ocasio-Cortez has also proven to have an important voice as a validator of progressive policy proposals -- demonstrating an ability to elevate lesser-known candidates and cause headaches for those at the front of the field.

Washington Gov. Jay Inslee has built his candidacy around the argument that he has the strongest record, and is the most focused, on combating climate change.

When Inslee released a lengthy climate proposal last week, Ocasio-Cortez turned her progressive following toward it, tweeting that Inslee's plan was "the most serious + comprehensive one to address our crisis in the 2020 field."

Inslee spokesman Jared Leopold said his campaign saw a clear spike in Google searches around the time of Ocasio-Cortez's tweet, and attributes part of a boost to its number of donors around the time of the policy rollout to her highlighting the policy.

Former Vice President Joe Biden, meanwhile, drew Ocasio-Cortez's ire earlier this month when one of Biden's advisers touted the need to find "middle ground" in an interview with Reuters.

Biden's campaign has since said the interview does not reflect its views on climate policy. But the political damage was done.

"I will be damned if the same politicians who refused to act then are going to try to come back today and say we need a 'middle of the road' approach to save our lives," Ocasio-Cortez said in a clear shot at Biden at a Washington, DC, event hosted by the Sunrise Movement, an activist group that backs the Green New Deal, where Sanders was also in attendance.

The comment led to news coverage of progressives' problems with Biden before he's had a chance to roll out his own climate policy proposal, which his campaign has said is coming soon.