Republican leaders expect William Weld to decide today whether he will stay in the race for governor after the state GOP chairman, a top supporter of Mr. Weld’s candidacy, reversed course and told him to clear the way for the party’s official designee, John Faso.

Mr. Weld faces a Thursday deadline to accept his automatic spot on the September primary ballot, a choice he earned after receiving more than 25% of the delegate vote at the party’s nominating convention in Long Island last week. As of last night, a spokesman for Mr. Weld’s campaign said the former Massachusetts governor had not decided whether to continue his bid.

The political maneuvering came on the same day the front-runner for the Democratic gubernatorial nomination, Eliot Spitzer, warned of “gathering storm clouds” in New York if leaders don’t curb population trends that show an exodus of more than 180,000 people from the Empire State between 2000 and 2004.

As Mr. Spitzer’s campaign moves aggressively after receiving the unanimous backing of the Democratic committee last week, Republican leaders are looking to unite behind Mr. Faso, a former Assembly minority leader who won the backing of a surprising 61% of GOP delegates at last week’s convention.

The party chairman, Stephen Minarik, said yesterday that he had urged Mr. Weld in a conversation over the weekend to drop out of the race “in the name of party unity.”

“John Faso earned the support of our convention and I think it’s critical we get behind him as we take the fight to Eliot Spitzer,” Mr. Minarik said in an interview.

Mr. Faso’s decisive victory at the convention was a defeat for Mr. Minarik, who had been staunchly in Mr. Weld’s corner and had at one point in the campaign derided Mr. Faso as being “in lala land.” Mr. Minarik is more ideologically aligned with the conservative Mr. Faso, but he backed Mr. Weld, a moderate, early in the race with the thinking that he could win swing voters as well as the key endorsement of the state Conservative Party. Mr. Weld was rebuffed by the Conservative Party chairman, Michael Long, who helped throw the party’s support to Mr. Faso, giving him a crucial boost in his bid for the GOP designation.

As late as this weekend, Mr. Minarik had resisted an endorsement of Mr. Faso, and party officials privately described his abrupt about-face as a last ditch effort to save his job as committee chairman.

Mr. Minarik said his decision yesterday was not about him, but about the party. “The party is bigger than one person,” he said. “Party chairmen come and go. Candidates come and go.”

He said it was important to get behind a single candidate now, “and not in September after a lengthy primary that wastes campaign resources.”

Mr. Minarik said Mr. Weld told him he would take the matter under consideration. Mr. Weld spent the day conferring with top advisers about what to do. “He’s not made a decision, and it could go either way,” a campaign spokeswoman, Andrea Tantaros, said. “Party leaders who he respects have called for unity, and we are giving them the serious consideration they deserve.”

A statement from the Faso campaign said Mr. Faso was “appreciative” of Mr. Minarik’s encouragement and would “continue to work hard to earn the support of all Republicans across the state, both leadership and grassroots alike.”

The Weld camp was of two minds yesterday, aides said. On one hand, Mr. Minarik’s decision to back off his support was seen as a final division between Mr.Weld and Governor Pataki, who many had expected to endorse Mr.Weld before last week’s convention. Mr. Pataki was said to be unhappy about repeated news stories emphasizing fractures in the Republican Party and feared that a primary battle would turn into a referendum on his leadership.

But even as Mr. Weld was considering ending his bid, campaign aides also offered a positive spin on yesterday’s announcement, holding that Mr. Weld was now liberated to run as a true outsider, echoing his successful bid for the Massachusetts statehouse in 1990. In that race, the fresh-faced Mr. Weld defied a state party chairman’s call to drop out.

Whether he could actually defeat Mr. Faso in a primary is another question. Mr. Weld received the majority support of delegates in 18 of the state’s 62 counties.The GOP chairman of New York county, James Ortenzio, estimated that 10 counties, including his own, were still behind Mr.Weld. “If Bill wants to tie himself to the mast, we’ll take him past the sirens,” he said.

While Republicans moved closer to picking a nominee, Mr. Spitzer, in Manhattan, cited recent census data that showed more people are leaving New York than any other state in the nation. “People are leaving because they can’t make ends meet here, and they are forced to look for better opportunities elsewhere,” he said, in a commencement speech to graduates of the City University of New York Honors College. Recalling his father’s climb to success from a tenement on the Lower East Side, Mr. Spitzer said New York had once been a beacon of hope and opportunity, but was now “desperately in need of a wake-up call and a dose of passion.”

“Today I ask you to stay in New York and help restore it to its former luster,” he told the 211 graduates at the Manhattan Center on West 34th Street. Mr. Spitzer made no direct mention of his gubernatorial campaign, and while expressing optimism that the state could revitalize its economy and become a capital of research, culture, technology, and science, he did not offer a specific plan to reverse the exodus he referenced.

The attorney general’s opponents in the governor’s race seized on his remarks to call for lower taxes. “The reason people are leaving New York are high taxes,” Mr. Faso said. “It’s not because of a lack of enthusiasm or passion. It’s because taxes are too high.”

Mr. Faso criticized Mr. Spitzer, saying he was asking New Yorkers to trust his “passion” without offering the specifics of a proposed remedy. “In that regard he’s really insulting the voters,” Mr. Faso said.

The campaign of Thomas Suozzi, Mr. Spitzer’s challenger for the Democratic nomination, echoed Mr. Faso’s remarks, saying the attorney general “doesn’t have the first clue on how to lower taxes or create jobs that would keep New Yorkers from leaving our state.”

Mr. Spitzer’s spokeswoman, Christine Anderson, responded that Mr. Spitzer “always said he’s against raising taxes. He thinks raising taxes runs contrary to what New York’s economy requires and what New York families can reasonably sustain.”