Graham Platner, the likely Democratic nominee for Senate in Maine who is facing new scrutiny of his past behavior, came to Washington on Tuesday and drew a nervous and somewhat standoffish reception from the Senate Democrats he hoped to join.
Mr. Platner, an oyster farmer who is running against Senator Susan Collins, a five-term Republican, invited the entire Senate Democratic caucus for an afternoon meeting, but only about half a dozen senators were seen entering the building for the meeting.
Earlier, Mr. Platner had a 30-minute, one-on-one session with Senator Chuck Schumer of New York, the minority leader, according to two people briefed on the meeting. Mr. Schumer had endorsed Mr. Platner’s primary opponent before she suspended her campaign a month ago.
Speaking to reporters at the Capitol, Mr. Schumer dodged repeated questions about Mr. Platner after reports last weekend that the candidate had sent sexual messages to women outside his marriage. The revelations stoked worries among some Democrats that Mr. Platner, who has already survived several controversies, has more political baggage that has yet to emerge.
“I met with Graham Platner today,” Mr. Schumer said. “We’re going to beat Susan Collins and take back the Senate.”
As reporters pressed Mr. Schumer about his confidence in Mr. Platner, he repeated three more times that Democrats would defeat Ms. Collins — and noted once that he had endorsed Mr. Platner — before ending his news media availability.
Mr. Schumer’s clipped responses to questions about Mr. Platner were echoed by the few Senate Democrats who crossed Constitution Avenue from their offices to meet with Mr. Platner at the headquarters of the Senate Democratic campaign arm. The 90-minute session, which came after an invitation from Mr. Platner’s aides, was planned before last weekend’s reports about his texts to women.
Asked if Mr. Platner had answered questions about his past, Senator Kirsten Gillibrand of New York, the chairwoman of the campaign arm, replied: “Yes, he did. It was a good meeting.”
Others who met with Mr. Platner, including Senators Elizabeth Warren of Massachusetts, Tina Smith of Minnesota and Peter Welch of Vermont, said even less or did not respond to questions.
Senator Bernie Sanders, independent of Vermont, did not engage with questions about Mr. Platner’s past conduct, but criticized Republican attacks against him.
“Why are they spending so much money trying to defeat this guy?” Mr. Sanders said on his way into the meeting. “The answer is that he’s going to stand up to the oligarchs. Thank you very much.”
Mr. Platner himself entered and exited the Senate Democratic campaign headquarters without saying a word. The informal meeting was a cordial gathering in which Mr. Platner’s explanations of his behavior largely tracked with his public accounting, according to two people briefed on the conversations.
Also on Tuesday, Mr. Platner pulled out of a planned event on Wednesday with VoteVets, a Democratic organization that backs veterans running for office, according to two people familiar with the plans. VoteVets endorsed Mr. Platner last month, three weeks after Gov. Janet Mills, his leading primary opponent, suspended her campaign.
Ben Chin, Mr. Platner’s campaign manager, said the candidate had left Washington to return to Maine because his wife’s family was growing uneasy about a growing media presence outside their home and family restaurant.
Mr. Platner has been the presumptive Democratic nominee since late April, when Ms. Mills, the choice of Mr. Schumer and the Democratic establishment, stepped away from the race, citing a lack of financial resources. It was an extraordinary sign of the progressive momentum behind Mr. Platner, 41, a political neophyte who has drawn big crowds in Maine. The race is widely seen as a must-win for Democrats in their uphill push to retake the Senate.
But some Democrats, publicly and privately, have continued to harbor reservations about Ms. Platner’s candidacy. Last year, he faced controversies over a chest tattoo he had that resembled a Nazi symbol (he later had it covered up) and over old Reddit posts that were dismissive of sexual assault survivors or inflammatory in other ways.
Ms. Mills, in comments published on Monday, reminded Maine voters that she was still on the ballot in the state’s primary next week.
“People have the impression that I ‘withdrew’ or ‘dropped out,’” she said in an interview published in The Portland Press Herald. “I simply suspended active campaigning. I am still on the ballot.”
Mr. Platner’s meeting with Senate Democrats drew a crowd of dozens of journalists and onlookers, which included a number of Republican protesters chanting about Mr. Platner’s texting.
The invitation for the meeting from Mr. Platner’s aides called the session an “informal member-only meet-and-greet.” It continued with a request for senators to send a donation to Mr. Platner’s campaign before Maine’s primary next Tuesday.
Most Senate Democrats declined the invitation.
One of them, Senator John Fetterman of Pennsylvania, nodded to reports that Mr. Platner appeared to have had an account with the username Phustle0331 on Kik, a messaging app known for anonymous communication.
“I didn’t match up from kik,” Mr. Fetterman quipped in a text message. “What’s up, P-Hustle!?”
Lisa Lerer and Katie Glueck contributed reporting.
