Hillary Rodham Clinton's all-but-announced Senate candidacy in New York became even more of a foregone conclusion yesterday, as the only other potential Democratic candidate said she is dropping out of the race because it is "clear" that Clinton will run.

Rep. Nita M. Lowey (D-N.Y.) yesterday said she is withdrawing from the Senate race to clear the field for the first lady and will instead run for a seventh term in the House. Advisers to Hillary Clinton said she plans to announce the formation of an exploratory committee in early July, and while some still caution that she could change her mind, the adopted-state candidacy that once seemed almost too far-fetched to contemplate is looking more than ever like a done deal.

Clinton, who has never lived in New York and has never run for elective office, met yesterday to talk politics with James Carville, the charismatic consultant so central to her husband's 1992 presidential campaign. Carville said the first lady never declared to him that she was running during their chat, but he said the assumption was obvious.

"I don't know if I've ever declared to her that I'm a male," Carville said. "It's understood."

Now that Lowey has pulled out, Clinton is the only Democrat even considering the race to succeed retiring Sen. Daniel P. Moynihan (D-N.Y.); New York Mayor Rudolph W. Giuliani and Rep. Rick Lazio (R-N.Y.) are likely to compete for the Republican nomination. Lowey, who had pledged to run for Senate if Clinton did not, said she simply realized that the first lady is acting like a candidate and talking like a candidate because she is a candidate.

"She's clearly made the decision to run," said Lowey, who called Clinton yesterday and pledged to support her still-undeclared candidacy. "It was time for me to move on."

Lowey did not rule out the possibility of getting back into the race if Clinton has a change of heart, but Democratic insiders say the party is obviously counting on the first lady to run. Potential candidates such as state Comptroller Carl McCall, Housing and Urban Development Secretary Andrew M. Cuomo and environmental activist Robert F. Kennedy Jr. have already taken their names out of circulation, and Clinton advisers acknowledged yesterday that she would put the party in an uncomfortable position were she to forgo the race.

"The ante has been upped on Hillary," one top adviser said.

Other Democrats were even blunter about the first lady's responsibility to the state and national party. Polls suggest that even for Clinton, one of the best-known and most-admired women in America, a celebrity showdown with the pugnacious Giuliani -- who pointedly joked during her visit to Manhattan on Tuesday that he was thinking about a visit to Arkansas and yesterday quipped to reporters that "exploring New York is a good thing" -- would be no cakewalk. And the longer she stays in the mix, the harder it would be to replace her. "At this point, if she doesn't run, we're screwed," one New York operative said.

For now, though, everyone's assumption is that Clinton is running, even though she has no real ties to New York, even though she just lived through the nightmare of impeachment, even though she would undoubtedly face a barrage of uncomfortable questions about Whitewater, her high-profile failure to deliver a national health insurance plan and her unusual success in the cattle futures market. When Lowey suggested to Clinton yesterday that she had clearly made up her mind to run, she did not agree, but she did not disagree, either. And while Clinton advisers have been saying for a while that she plans to form an exploratory committee in early July, Harold Ickes yesterday was the first to say so on the record.

"She's pressing forward," he said. "The creation of an exploratory committee would be the obvious next step."

Clinton's interest in the Senate race was evident Sunday at a private meeting in Florida, as she buttonholed a number of Democratic activists for advice about sharpening and shaping her message. Sources said that during breaks from a day-long forum sponsored by the centrist Democratic Leadership Council, she quizzed insiders such as DLC Director Al From, former White House communications director Donald A. Baer, White House pollster Mark Penn, and New York Democratic activists Lynn Forester, Bob Burkett and Bob and Ronay Menschel.

President Clinton, a former DLC chairman, has championed some causes that have angered liberal Democratic constituencies, such as free trade and welfare reform, but no one is quite sure whether his wife plans to echo those ideas during a campaign in New York. Sources said that at the forum, the first lady batted around ideas about the politics of trade and Social Security, wondering how a New York politician can appeal to both moderates and liberals.

"She clearly is engaged in the challenge of trying to think about how you continue to offer innovative ideas for governing, but without creating ruptures in the broader Democratic coalition," said Will Marshall, president of the Progressive Policy Institute.

Hillary Clinton is an eloquent and often inspiring speaker, and there is no doubt that she could be a prodigious fund-raiser. The national media are dying for her to run, and Democrats see her as a possible future president. But the prospect of a first lady running for office in New York while her husband is running the country in Washington is still a bizarre scenario, and Clinton associates cautioned that it hasn't happened yet.

"This is obviously moving ahead in one direction," said Democratic consultant Mandy Grunwald, another Clinton adviser. "I think she's where she was yesterday and the day before and the day before that. But she hasn't made an announcement. That's where we are."

Staff writer Charles Babington contributed to this report.