On a day of back-room maneuvering and deal-making, Mr. Thompson’s own inner circle appeared divided over how, or even whether, to proceed, with his campaign. Mr. Thompson vowed to press on, but the chairwoman of his campaign said Mr. de Blasio had won a “clear victory” and suggested the race was over. “I don’t think there’s much appetite within the Democratic Party to have a fight here,” Merryl H. Tisch, the campaign chairwoman, said in a telephone interview.
Mr. de Blasio, eager to cement his status as the Democratic nominee, quickly acted to project an air of inevitability by wooing labor unions that had supported his rivals. Several unions that had snubbed Mr. de Blasio in the primary moved quickly to endorse him, arguing that it is in the best interests of their members and their party.
A longtime ally of Mr. Thompson, the Rev. Al Sharpton, encouraged him to give up his campaign, and an influential labor group, the Hotel Trades Council, endorsed Mr. de Blasio.
“It’s time for working people and Democrats to unite behind our next mayor, Bill de Blasio,” said Josh Gold, political director of the Hotel Trades Council.
Mr. Thompson found some measure of hope in the uncertain election outcome. With 99 percent of precincts reporting, Mr. de Blasio had won 40.3 percent of the vote, just over the 40 percent required by law to avoid a runoff, but there were more than 16,000 paper ballots, some still arriving by mail, that could push Mr. de Blasio below that threshold when they are counted next week.
