Vice President Joe Biden left the seclusion of the Delaware home where he’s been weighing a presidential run to meet Saturday with Elizabeth Warren ― another influential Democrat who has faced calls to enter the 2016 race.

The unusual weekend huddle with Warren, a Massachusetts senator, took place at the Naval Observatory, the vice president’s official residence, said an individual familiar with the meeting. An Obama administration official said Biden had traveled at the last minute to Washington for a private meeting and planned to return to Delaware the same day. Both of the individuals spoke on condition of anonymity because they weren’t authorized to discuss the meeting publicly.

Biden’s meeting with Warren was the latest sign that the vice president is seriously considering entering the race, and that he’s increasingly discussing it with Democratic leaders outside of his small cadre of longtime advisers.

A rising star in the party, Warren was the subject of an intense lobbying campaign by a group called Draft Warren that sought to persuade her to enter the race. Warren ruled out running in 2016, and a super PAC similarly named Draft Biden later emerged and has been laying the groundwork for a potential Biden candidacy.

Warren, a vocal advocate for economic fairness and Wall Street reform, has notably refrained from endorsing Hillary Rodham Clinton, Sen. Bernie Sanders or the other candidates. She retains the vocal support of many in the liberal wing of the Democratic Party, making her endorsement one of the most highly sought in the primary.

Biden’s quick trip to Washington wasn’t on his official public schedule, which listed him as remaining in Delaware through Sunday. He’s spent the past several days at his home in a secluded, wooded suburb of Wilmington spending time with family ― but also meeting with his longtime political aides to assess what it would take to launch a viable presidential campaign against well-funded Democratic opponents with a huge head start.

Spending time with Biden in Delaware were longtime Biden confidantes Mike Donilon and former Sen. Ted Kaufman, along with his sister, Valerie Owens Biden, who has played a top role in all his previous campaigns. The Associated Press first reported on the Delaware meeting, while CNN first disclosed the session with Warren.

Although Biden has yet to make a decision, his advisers have started gaming out mechanics like fundraising, ballot deadlines and an early primary state strategy. Another key consideration is the personal consequences for Biden and his family, who are still mourning the death of the vice president’s son, Beau Biden, a few months ago.

Biden’s team has settled on a one-month window in September in which he could potentially announce plans to run.

The longer he waits, the less time he has to build a formidable campaign. But competing events on the administration’s calendar make it difficult to launch in the next couple of weeks, making it more likely an announcement would wait until late September, aides said.

If Biden’s not in by Oct. 1, it will be increasingly difficult for him to run, people who have spoken to Biden recently said. He’ll need at least two full months to get the petition signatures and delegates lined up by the beginning of December to qualify for the ballot in early primary states.

Biden’s aides are also eyeing the first Democratic primary debate ― on Oct. 13 ― as potentially a make-or-break moment. That first debate is expected to attract a huge audience among Democratic primary voters, giving Biden a powerful opportunity to establish himself as a credible alternative to Clinton. (AP)