"What I would like to see in a presidential candidate is one that has a coherent worldview and logic from which all these policy proposals are coming forward," Ocasio-Cortez said. "I think Sen. Sanders has that. I also think Sen. Warren has that."
Asked for more specifics about when she would make an endorsement, her spokesman, Corbin Trent, said it would be early enough to have an impact.
"She wants to make sure her endorsement matters in the race," he said. "Timing is important."
One candidate she almost surely will not endorse in the early primaries is Biden.
He "does not particularly animate me," she said in an interview earlier this spring with the Yahoo News podcast "Skullduggery."
But she was, perhaps surprisingly, prepared to be a party loyalist in the end: "I will support whoever the Democratic nominee is," she said.
For Democrats other than Warren and Sanders, association with Ocasio-Cortez could be risky: Party centrists worry about her high profile as a democratic socialist. She has become the poster child for Republicans' cornerstone strategy for 2020 -- portraying the entire Democratic Party as pursuing a socialist agenda.
Republicans believe their job has been made easier since several 2020 Democratic presidential candidates, including Biden, the self-styled centrist, have embraced Ocasio-Cortez's signature issue -- the Green New Deal agenda for combating climate change.
"The fact that Joe Biden is embracing the Green New Deal shows you how far left the Democratic Party has gone," said Michael McAdams, spokesman for the National Republican Congressional Committee, the political arm of the House GOP.
A March Quinnipiac University poll found that more people (36%) had an unfavorable view of Ocasio-Cortez than a favorable one (23%). But 38% didn't know enough to have an opinion. Opinion was of course deeply split by party: 74% of Republicans viewed her unfavorably; just 7% of Democrats did.