Democrat Andrew Cuomo, New York’s attorney general and son of former three-term New York Gov. Mario M. Cuomo, is the likely front-runner for the Senate seat vacated by Hillary Rodham Clinton , according to several House Democratic aides.

That analysis came Wednesday night after news broke that Caroline Kennedy, the member of another Democratic family political dynasty, had decided that she is no longer seeking the appointment to the seat. That word came at the end of the day on which Clinton, the former first lady to President Bill Clinton, was confirmed and sworn in as secretary of State in the new Obama administration. Clinton immediately resigned the Senate seat she had held for eight years, after winning elections in 2000 and 2006.

Kennedy released a statement late Wednesday night saying she had notified Democratic Gov. David A. Paterson that she no longer wished to be considered for the Senate seat, citing personal reasons. That statement cleared up confusion that had developed earlier over conflicting news reports about whether she had or had not opted out.

Paterson’s office issued a release Thursday afternoon citing a “private conversation” between the two on Wednesday and that Kennedy’s decision was “hers alone.” It also noted that Paterson is in the “final phase of his selection process” for Clinton’s replacement but he “has not informed any Senate candidates that they have not been selected, nor has any information gathered during this selection process created a necessity for any candidate to withdraw.”

Paterson’s office issued an announcement that he will announce his selection at noon Friday.

Kennedy’s famous name — she is the 51-year-old daughter of the late President John F. Kennedy and niece of Massachusetts Sen. Edward M. Kennedy and the late New York Sen. Robert F. Kennedy — had made her the focus of attention for several weeks after she informed Paterson, other state Democratic officials and the press that she was interested in succeeding Clinton. Kennedy, who has been involved in civic affairs but has never run for public office, made several appearances around the state. There was intense speculation in recent days that her appointment by Paterson was virtually inevitable.

Paterson, however, said that while he was impressed with Kennedy, he also was considering other candidates. He acknowledged recently that Cuomo was among those he had interviewed for the interim appointment, which will run until a special election is held in 2010 to fill out the final two years of Clinton’s unexpired term. Paterson is now expected to make an announcement about the appointment on Saturday.

Cuomo has Washington experience as the secretary of Housing and Urban Development from 1997 to 2001 under President Clinton. Cuomo -- also 51 years old -- was born nine days after Caroline Kennedy in 1957 and was formerly married to Kerry Kennedy, a daughter of Robert F. Kennedy and cousin of Caroline Kennedy.

The celebrity surrounding Kennedy initially gave her a lead in polls of New Yorkers asked who should be appointed to succeed Clinton. But questions about her experience raised by some skeptical New York Democratic officials, reinforced by her lackluster performances in some TV interviews and public speeches, enabled Cuomo to surpass her in recent polls about the appointment.

The New York media gave conflicting reasons for Kennedy’s withdrawal. The New York Times reported that Kennedy’s decision was prompted by concerns about the health of Edward M. Kennedy , the longtime senator, who is fighting brain cancer and was briefly hospitalized after suffering a seizure during President Obama’s inaugural lunch Tuesday. But the New York Post, which broke the story, wrote that Kennedy withdrew after learning that she was not Paterson’s choice for the seat. Paterson and his aides have made no statement about the circumstances.

Whatever the motive, the move shakes up the unofficial race for the appointment. Despite Cuomo’s own prominence and family ties, Kennedy’s withdrawal at least gives some hope to other would-be contenders who had been overshadowed.

Four House Democrats have expressed interest in the Senate seat. They are Jerrold Nadler and Carolyn B. Maloney from Manhattan, Steve Israel of Long Island and Kirsten Gillibrand of the upper Hudson Valley. Maloney, though, was recently installed as chairwoman of the congressional Joint Economic Committee, taken by some as a possible signal she is out of the running for the Senate seat.

Gillibrand, seen by some Democrats as one of the fast-rising stars in the state party, has been a dark-horse candidate for the appointment. A member of the Blue Dog coalition of centrist House Democrats, she is less liberal than many of the contenders, a positioning that has helped her score two House wins in a district that typically favored Republicans in the past. In the process, she has exhibited prodigious skills as a campaign fundraiser, which she has employed for the party’s benefits as well as for her own campaigns. She has channeled donations to other Democratic candidates through her leadership political action committee, Gillibrand Victory Fund, which raised $305,000 in the 2007-08 election cycle.