With Caroline Kennedy’s departure early Thursday from the New York Senate sweepstakes, attention is now focused on state Attorney General Andrew Cuomo (D) and, to a lesser extent, Rep. Kirsten Gillibrand (D) as the leading contenders to replace secretary of State Hillary Rodham Clinton as New York’s junior Senator.

The confusion over Kennedy’s plans in the past 24 hours — which ended only after she issued a terse statement of withdrawal shortly after midnight — may prompt New York Gov. David Paterson (D) to accelerate his announcement of Clinton’s successor, which had been expected to come on Saturday.

For weeks, Kennedy, the daughter of the late President John F. Kennedy, was presumed to be the frontrunner for the appointment. Even after Kennedy’s rocky entry into the rough and tumble of New York politics last month, it was widely assumed that Paterson would not be able to resist the entreaties of the powerful Kennedy family to install one of their own in the Senate.

Paterson, like the Senator he will name, was a replacement in the governor’s office, and must run for a full term next year and share the ballot with his Senate appointee. While Paterson publicly embraced the idea of fielding a diverse statewide Democratic ticket in 2010, the simple fact is that he will need as strong a Senate candidate as possible — someone with fundraising firepower in particular. Kennedy was seen as fitting that bill.

But Cuomo and Gillibrand are themselves prodigious fundraisers — Cuomo collected more than $3 million for his statewide campaign account in the final six months of 2008, and Gillibrand spent more than $4.4 million on her re-election in the previous cycle — and Cuomo is a proven statewide vote-getter with a strong family network of his own.

Other potential appointees are Reps. Brian Higgins, Steve Israel, Carolyn Maloney and Jerrold Nadler and Nassau County Executive Tom Suozzi. All are Democrats.

Although Paterson and Cuomo have a complicated relationship — Cuomo would like to be governor some day — and the state’s senior Senator Charles Schumer (D) may not want to share the spotlight with the brash attorney general, the appointment may make the most political sense.

What may be complicating his decision is the question of who would replace Cuomo as attorney general. That rests with the state Legislature. The state Assembly, which is dominated by Democrats, will have particular sway over the selection. Late Wednesday night, Paterson was said to be talking with legislative leaders about prospective Cuomo replacements.

Although one state assemblyman, Richard Brodsky (D), who represents suburban Westchester County, was seen as the early favorite of Assembly leaders, an assemblyman from Queens, Michael Gianaris (D), is emerging as a compromise pick. His selection would represent a victory for Rep. Joseph Crowley (D-N.Y.), who doubles as chairman of the Queens County Democratic Committee.