Read: Is Joe Biden running for president? He can’t decide.

Biden pulled the plug at the last minute in 2015, and some of those closest to him warn he still may this time.

Biden has said as much himself.

In January, he went to the New York offices of BlackRock, the major investment firm, for a meeting with Larry Fink, the CEO. They talked about the state of the world and the country, about what’s going on in the markets. Toward the end, Fink said to Biden, “I’m here to help,” according to people told about the conversation.

Biden took it as an offer to sign on with the campaign.

“I’m 70 percent there, but I’m not all the way there,” Biden told Fink.

That same 70 percent line has been circulating among Biden allies for weeks: This looks like it’s happening, but don’t write off the 30 percent chance that it doesn’t. In that time, people who’ve spoken with Biden and those around him say he is still anguishing over both whether there’s a path to victory and whether running is the right thing to do for those closest to him, knowing that his record would be attacked and sensitive questions about his family would be aired in public.

Read: Why Joseph Crowley’s defeat should scare Joe Biden

“His heart is saying, ‘Go. It’s the thing you’ve always wanted,’” said one person who’s been in touch with Biden’s staff. “His head is assessing whether there’s an opening.”

Trump worries and offends Biden, and he feels a sense of duty to the government and the country to get things back on track. He fears that other Democrats can’t beat Trump and aren’t prepared for what it would be like to take over the government in his wake. Notably, no other announced or prospective candidate has any foreign-policy experience.

But over two presidential runs, and an additional two times he came very close to jumping in, Biden has struggled to put together effective campaign operations. This time around, multiple top Democrats who express deep affection for him say they also worry that he is underestimating how hard a campaign would actually be to pull off—let alone the damage it could do to his reputation or what the exposure would mean for his family.

Read: The geopolitical therapist

Biden is weighing his decision without any official polling or focus groups. He and his team have been talking with John Anzalone, a Democratic pollster who worked for both Barack Obama and Hillary Clinton. His ties go back to 1987, when he worked as an organizer in Iowa for Biden’s first White House run.

In several meetings recently, Anzalone laid out the realities of the Democratic-primary electorate based on public polling and election results from 2016 and 2018, concluding that it’s not as left-leaning or as young as it’s often portrayed. Biden has shown the document to other visitors, trying to decode what appetite exists for a centrist who is unapologetic about wanting to work more with Republicans, and who will turn 78 years old two weeks after Election Day 2020. Anita Dunn, who served briefly as White House communications director for Obama and is a Biden friend, has also been advising informally.