As New York and national Republicans turn their attention to their high-profile effort to unseat Sen. Hillary Rodham Clinton (D), they are confronted with the reality that they have no obvious challenger — and that the state GOP is in a period of transition, even uncertainty.

Many Republicans believe they have a chance to defeat Clinton in 2006 — or at least bloody her as she prepares for a widely-expected White House bid in 2008.

“Clearly, in my mind, Hillary Clinton is running for president in 2008,” said Stephen Minarik III, the newly installed chairman of the New York Republican Party. “She faces the task of answering for the voters, ‘OK, you’re running for president. Why do you want to run for U.S. Senate?’”

But to some Empire State political operatives, the fact that outgoing Secretary of State Colin Powell’s name was floated this week as a possible contender is a sign of the GOP’s weakness. Powell, who grew up in the Bronx but hasn’t lived in New York in decades, hasn’t given the slightest hint that he is looking at the Senate race.

New York has no shortage of superstar Republicans. But by all indications, the top two — Gov. George Pataki and former New York Mayor Rudy Giuliani — are both looking to run for president in 2008 and have no interest in a tough race against Clinton, despite the publicity it would bring.

Moreover, Pataki hasn’t said whether he plans to run for a fourth term in 2006, meaning that the GOP faces the daunting possibility of having to find someone new to head the statewide ticket in a likely race against popular state Attorney General Eliot Spitzer (D) even as they recruit someone to run against Clinton.

All of New York’s statewide offices are up in 2006, and all besides the governorship are held by Democrats, making the GOP’s task of staying competitive in a Democratic-leaning state all the more challenging. Democrats even believe they now have a shot at taking control of the state Senate, which has been in Republican hands for 40 years.

Minarik, the former Monroe County GOP chief who only took over the state party on Tuesday, is said to be especially eager to get a well-known candidate into the Senate race as quickly as possible — a sentiment national Republicans and “Hillary haters” no doubt share.

“I want to get the best possible candidate at the earliest possible date,” Minarik conceded.

But that wish may be at odds with the goals of his patron, Pataki, who is deliberative by nature and is expected to take as long as he possibly can before revealing his plans for 2006 and beyond.

“Right now, the governor is completely focused on running New York state, and he’ll make a decision about his future at the appropriate time,” said Lisa Dewald Stoll, Pataki’s communications director.

In the presidential sweepstakes, Giuliani appears to be way ahead, at least for now. He’s the top choice of Republicans nationally, according to recent polls, so there appears to be little need for him to run for Senate (or for governor, if Pataki doesn’t seek re-election).

By contrast, some pundits have suggested that Pataki may have to defeat Clinton in 2006 to attain the star status held by “America’s Mayor” — Giuliani — in the presidential contest. But several Republican operatives in New York and Washington, D.C., suspect that Pataki doesn’t have the stomach for such a bruising contest.

The fact that Pataki’s handpicked former state GOP chairman, Sandy Treadwell, just became New York’s Republican National Committeeman is seen as a further sign that Pataki is thinking about a national run and wants one of his top lieutenants to closely monitor the RNC.

Stoll said Pataki is mindful of his role as unofficial head of the state Republican Party and will help state and national GOP leaders find a strong Senate candidate.

“We don’t think there will be a problem recruiting candidates to take on Senator Clinton,” she said. “There should be a line at the door.”

Giuliani’s spokeswoman, Sunny Mindel, did not respond to an inquiry for this story Wednesday.

New York Republicans take some comfort in knowing that the national GOP and Republican interest groups will devote huge sums of money to defeating or injuring Clinton in the next few years. And beyond Giuliani, Pataki — and even Powell — there are other celebrity Republicans who could come out of the woodwork to run for Senate. (One state GOP operative said he wouldn’t be surprised to hear the name of conservative Fox News Channel host Sean Hannity in connection with the Senate race, even though there is no serious talk of him running.)

But the presence of potential big-name challengers also fuels Clinton’s formidable money machine. A recent solicitation by the Senator used the specter of a challenge by Giuliani or Pataki as the basis for raising money.

While she is inevitably aware of her possible foes, Clinton is concentrating on her day job, adviser Howard Wolfson insisted.

“The best way you prepare for a possible opponent is you do your best job possible as a Senator,” he said.

Beyond the celebrity list, state GOP leaders say there are any number of Republicans who could run for Senator, governor or other statewide offices in 2006, including Reps. Peter King and John Sweeney, Erie County Executive Joel Giambra, Westchester County District Attorney Jeanine Pierro, state Sen. Michael Balboni and former Rep. Rick Lazio, Clinton’s opponent in 2000, who took 43 percent of the vote in their matchup.

New York Secretary of State Randy Daniels (R), who was appointed by Pataki, has all but declared his intention to run for governor if Pataki doesn’t seek re-election. A source close to Daniels said Wednesday that the Democrat-turned-Republican would “take a look at other things” in 2006 if Pataki runs again.

One Republican source offered another possible name for Senate in 2006: Housing and Urban Development Deputy Secretary Roy Bernardi, a former mayor of Syracuse. Bernardi was monitoring appropriations deliberations on Capitol Hill on Wednesday and could not be reached for comment.

As for Powell, Minarik said he would reach out to the departing secretary of State as soon as possible.

Rep. Vito Fossella (R-N.Y.) floated the idea of a Powell Senate candidacy Tuesday, releasing a letter he wrote to Powell urging him to run.

Craig Donner, a spokesman for Fossella, said the Congressman spoke to the secretary after publicizing the letter but would not reveal details of the conversation. But Donner said his boss is hoping that Powell can be persuaded to run, comparing Fossella’s early entreaties to the suggestions Rep. Charlie Rangel (D-N.Y.) first made to get Clinton to run for Senate.

“You never can tell how these things progress,” Donner said. “They take on a life of their own.”

Wolfson said the Clinton camp would have no comment about the Powell boomlet.