ALBANY – The unofficial race against Senator Clinton began in earnest yesterday as Edward Cox named an exploratory committee of prominent state and national insiders, accused the former first lady of using New York as a stepping stone to the presidency, and demanded that she pledge, if re-elected, to serve out her term.

Speaking by telephone after announcing the membership of his exploratory committee at the Women’s National Republican Club at Rockefeller Center, Mr. Cox said voters in New York resent Mrs. Clinton for “parachuting” into the state and using it as a “springboard.” He said she cannot both run for president, as she is thought to intend, and advocate single-mindedly for her constituency here.

“She needs to make that commitment that she is going to fill out her term if she were re-elected,” Mr. Cox said, “and I don’t see her being able to make that commitment.”

In naming a 31-person committee that includes a secretary of state under Richard Nixon, Henry Kissinger; a former White House chief of staff, Kenneth Duberstein; and a former NATO ambassador, William Howard Taft IV, Mr. Cox has assembled a group that has been crafted to include state and national figures for a campaign that he and others expect will be national in scope.

The race against Mrs. Clinton is likely to be the most expensive ever, and Mr. Cox, a Manhattan attorney who married Nixon’s daughter Tricia, is aiming to show skeptics that his 30 years in state and national Republican circles have given him the access and experience he will need not only to raise money on a grand scale but also to challenge as formidable a candidate as the former first lady.

One early skeptic of the Cox campaign is the chairman of the New York Republican State Committee, Stephen Minarik, who openly backs the district attorney from Westchester County, Jeanine Pirro, for the race against Mrs. Clinton. Mrs. Pirro has said she will run for statewide office but has not said which of next year’s campaigns – for governor, attorney general, or U.S. Senate – she plans to enter.

Asked about Mr. Minarik’s support for a Republican candidate who has not yet declared an interest in the race, Mr. Cox pointed to the support he has so far received from other prominent Republicans.

“I do know that as we were getting ready for this race, the governor called me and urged me to run and has been very helpful, and the same is true for the second most powerful Republican in the state, Joe Bruno,” Mr. Cox said. “We have senators from across the state who are supporting us, and we have put together a great team in terms of fund raising, issues, and mechanics.”

Mr. Cox, a partner in the corporate law firm Patterson Belknap Webb & Tyler, is a 10-year trustee of the State University of New York and chairman of the New York League of Conservation Voter Education Fund. A major theme of his campaign, he said, would be the importance for New Yorkers of having a representative from their state in the majority party in Washington. He said the current senators, Mrs. Clinton and Charles Schumer, lack “clout.”

“Hillary Clinton is out of power in Washington,” Mr. Cox said. “Despite all the glitz she has, people forget she is in the minority. We don’t have the bipartisan representation we used to have, that can really produce results. We have two liberal Democratic senators, and they just don’t have the clout we need to have New York get its fair share.”

In response to Mr. Cox’s remarks about carpetbagging, a spokesman for Mrs. Clinton, Howard Wolfson, told The New York Sun: “While the Republicans sort out their nominating process, Hillary Clinton will continue to stay focused on working for New Yorkers.”

Mr. Cox said he would make a decision on whether to run sometime this fall. He noted that – in addition to the high-profile names on the exploratory committee – a prominent Republican pollster, Fred Steeper; a fund-raiser for Mr. Pataki, Cathy Blaney; and a direct-mail marketing firm once owned by a top White House adviser and Bush administration strategist, Karl Rove, would be involved in his potential campaign.

“We have already put in place a very top-flight team,” Mr. Cox said. “Quality attracts quality. But the main thing is, I will take my record of service to three presidents and two governors and match it against Mrs. Clinton any day.”