ALBANY – When David Kelley became Manhattan’s top federal prosecutor in December 2003, he knew the job was temporary. President Bush had just rewarded U.S. Attorney James Comey, a Republican, with the no. 2 job at the Department of Justice, but Mr. Kelley, a Democrat, was told not to expect a permanent appointment, sources said last week.

Yet nearly 15 months later, Mr. Kelley not only continues to run the U.S. Attorney’s Office for the Southern District of New York, but the deputy position he left to take the job also remains unfilled. That Mr. Kelley has run the office for so long without explicit political endorsement is a testament to his talents as a prosecutor, his associates and former colleagues said.

Others who have followed the situation, however, said that despite Mr. Kelley’s abilities in the courtroom, the real reason for his unexpectedly long tenure heading the office could be partisan politics and White House inattention. At issue: a possible breakdown in the appointment process that threatens to create a leadership vacuum in an office that has traditionally played an important role in the fight against terrorism.

“David Kelley is well thought of, though I’m surprised they let a Democrat stay there this long,” a veteran defense attorney, Murray Richman, said.

“He’s top notch, but I don’t know what they’re doing,” Mr. Richman, who has 19 pending cases before federal court in New York, told The New York Sun. “I have not even heard rumors of names, and usually I’m pretty good at getting the rumors.”

The U.S. attorney’s office for the Southern District routinely handles some of the most high-profile criminal cases in the country. Its prosecution of mafia hit men and white-collar criminals and its near monopoly of domestic terrorism cases in the past decade have reinforced its nickname as the Sovereign District of New York.

The office consists of a lead attorney, a deputy, 225 assistant U.S. attorneys, and a support staff of 125. The top post is a presidential appointment, with individual U.S. attorneys typically holding the job for the length of a presidential term. Mr. Bush appointed Mr. Comey after President Clinton’s pick, Mary Jo White, left for private practice early in 2001.

When a U.S. attorney leaves the post, as Mr. Comey did, the attorney general names a four-month replacement. When that term expires, the U.S. District Court that has jurisdiction over the office extends the acting replacement’s term indefinitely, until a presidential appointment is confirmed. In Mr. Kelley’s case, such an appointment has never come.

Still, federal prosecutors in Manhattan do not appear to be standing around waiting for a permanent leader to be named. Their office, which has long had a reputation for an aggressive approach that tends to favor long sentences rather than plea bargains, have won a number of widely publicized cases in the past year or so, including the conviction of the homemaking expert Martha Stewart last March and the recent conviction of the activist lawyer Lynne Stewart. Mr. Kelley and his team are currently looking to put away the former WorldCom chief, Bernard Ebbers, for his role in the nation’s largest corporate bankruptcy.

“Regardless of whether in certain circumstances in some places it would not be a good thing to have an acting U.S. attorney for a long time, in this instance the U.S. attorney for the Southern District who has the job, David Kelley, is one of the most able lawyers I’ve ever met,” a former assistant U.S. attorney in the office, Andrew McCarthy, said. “He’s got great credibility with the Justice Department, he’s got great credibility with the court, and whether he was there for five minutes or five years the office would be well served.”

Historically, the president defers to a senior member of his own party for nominees as U.S. attorney. With the exception of Mr. Kelley, all four of New York State’s current U.S. attorneys are Bush appointments. In most cases, Republican senators propose a candidate to Republican presidents, and Democratic senators propose a candidate to Democratic presidents. In the case of New York, however, where neither senator is of the same party as the president, Governor Pataki is expected to put candidates forward for presidential consideration. That was clearly the case when Mr. Bush chose Roslynn Mauskopf, a former Pataki administration official, as U.S. attorney for the Eastern District of New York.

Mr. Pataki’s role in picking candidates was also clear in the case of the U.S. attorney for New York’s Northern District, Glen Suddaby. Mr. Suddaby, who has held the post based in Syracuse for three years, said he was chosen by a committee that Mr. Pataki formed soon after Mr. Bush took office in 2001. Mr. Suddaby is among those who have not heard of any imminent replacements for Mr. Kelley.

“I haven’t heard anything in some time,” the upstate prosecutor said. “I knew there were some people who were under consideration during the election, but I haven’t heard a peep since then. Obviously, a president likes to have his presidentially appointed people in place, but David Kelley, from what I understand, is doing a fine job.”

Mr. Pataki declined to comment on the process for appointing U.S. attorneys or on the Southern District, saying through an aide that the job was a presidential appointment. Some have suggested that Mayor Giuliani, the state’s most popular Republican according to polls, has reserved the right to pick a candidate for the Southern District job.

According to one current assistant U.S. attorney, the reason for a delay in the first round was that one finalist was a White House pick and the other was a Pataki pick. The Bush administration didn’t want to insult Mr. Pataki by placing its own choice in the post over his, so it chose to leave the job vacant instead, the assistant U.S. attorney said.

Mr. Giuliani knows the Southern District job well, having served in it as a Reagan appointee in the early 1980s. It was Mr. Giuliani’s success in prosecuting mafia leaders as U.S. attorney that provided him with the tough-guy image he needed to beat David Dinkins in 1993.

One name that circulated for the U.S. attorney’s job last year was Bart Schwartz, who was Mr. Giuliani’s chief investigator at the time. Just last week, Mr. Schwartz opened the private investigation consulting firm Nardello Schwartz.

Another name that circulated last year was Lawrence Byrne, who, as an assistant U.S. attorney in the Southern District between 1988 and 1992, specialized in organized-crime and securities-fraud prosecution. Now a partner in the Manhattan law firm White & Case, Mr. Byrne denied he is currently being considered as a candidate for the post. He said Mr. Kelley’s replacement, if there is one, would probably come from Mr. Pataki.

“Obviously Rudy has a great relationship with the White House,” Mr. Byrne said. “But by tradition the senior Republican in the state is the one who recommends someone. I’m sure the White House will be consulting closely with Pataki on this.”

Still other names that circulated last year included those of Joseph Bianco, a former assistant U.S. attorneys who is now an assistant U.S. attorney general; Kerri Martin Bartlett, who left the Southern District office to raise her children; Michael Garcia, an assistant secretary at the Department of Homeland Security, and Robert Khuzami, a former assistant U.S. attorney now at Deutsche Bank, who spoke about the Patriot Act at last year’s Republican National Convention in New York.

One possible reason Mr. Comey’s permanent successor wasn’t named last year was uncertainty over the presidential election. With polls showing Senator Kerry and Mr. Bush in a dead heat for much of the summer, the prospect of assuming a job that could soon be up for grabs no doubt would not have appealed to some potential nominees. “You weren’t going to put somebody in there for three months,” a former assistant U.S. attorney, Jay Musoff, said. “For somebody to go in then, it’s a risk.”

Mr. Musoff, who now works at the New York firm Orrick, Herrington & Sutcliffe, said it could be premature to expect a new U.S. attorney at this point. He said that the inauguration was not that long ago in the scheme of things and that a second search could be getting under way.

“I don’t know why the Bush administration hasn’t acted sooner,” he said. “You hear rumors. But we’re only two months in.”

A spokesman for the White House, Ken Lisaius, said the Bush administration does not comment on personnel matters. “We’ll make an announcement when we have an announcement to make,” he said. “We do have an acting U.S. attorney, a person who is filling that role in an acting capacity.”

That message could be a sign that Mr. Kelley is indeed about to lose his job. Spokesmen at both the Justice Department and the U.S. attorney’s office in New York stressed that it is not accurate to describe U.S. attorneys who have not been appointed by the president as “acting” after their first four months on the job. By referring to Mr. Kelley as “acting,” the White House could be sending a signal as to its view of his status.

“I think their lingo is wrong,” a spokesman for the U.S. attorney’s office in Manhattan, Herbert Hadad, told the Sun. “He’s been U.S. attorney since April.”

Another possible reason for the delay is Mr. Kelley’s familiarity – both personal and professional – with terrorism. During the late 1990s, he was head of the U.S. Attorney’s Organized Crime and Terrorism Unit. While there, he investigated the bombing of the U.S.S. Cole in Yemen and led the unit’s successful prosecution of the man behind the 1993 World Trade Center bombing, Ramzi Yousef.

On September 11, 2001, Mr. Kelley experienced terrorism first-hand. According to a biographical sketch on the New York Law School Web site, he ran four blocks from his office to view the damage to the North Tower of the World Trade Center, arriving just as the South Tower collapsed. That night, the FBI drove him to Washington, D.C., to direct the investigation into the attacks. Mr. Kelley led the 9/11 task force until his promotion to be deputy U.S. attorney in June 2002.

“David is the most qualified U.S. attorney in the country with regard to terrorist organizations,” the director of the Trial Advocacy program at New York Law School, Eugene Cerruti, said. Mr. Kelley teaches a lecture class there.

“He’s been involved in those investigations in the pre-9/11 period,” Mr. Cerruti said, “so he’s been an invaluable resource within Justice all the way through.”

Some have suggested that Mr. Kelley’s connection to the attacks could make his removal politically risky. Others have said that perhaps Mr. Bush intends to keep him in place without ever naming a replacement – a potential deviation from the precedent Mr. Clinton set soon after his first inauguration by directing his attorney general, Janet Reno, to request the resignations of all of the 93 U.S. attorneys.

“If you look at most of the U.S. attorneys, almost all of them are presidential appointments,” an assistant professor at John Jay College of Criminal Justice, Brian MacNamara, said. “He’s been doing a very good job, so maybe the point is to just leave him in the position and don’t make him a presidential appointment.”

Not one person interviewed for this article, including defense attorneys who have gone up against Mr. Kelley in court, said the uncertainty surrounding his status has had an adverse effect on the office’s pursuit or prosecution of crime. And those who pointed out that different U.S. attorneys tend to focus on different types of crime said Mr. Kelley’s style and emphasis appear to complement the aims of the Bush administration.

“He’s carrying out his responsibilities in a manner which is consistent with what I believe the administration would want him to do,” a former assistant U.S. attorney for the Southern District, Richard Signorelli, said.

Mr. Signorelli, who now works as a criminal defense attorney in New York, said: “Whether it’s violent gangs, narcotics, securities fraud, or terrorism, David’s office is very strong and has had a string of successes.”

Mr. Kelley’s close relationship with top officials in the Justice Department could also explain his longevity. Former and current colleagues describe Mr. Kelley as the “best friend” of Mr. Comey, who, next to new Attorney General Alberto Gonzales, holds the department’s most senior position. Neither Mr. Comey nor Mr. Kelley responded to e-mail requests for an interview.

According to Mr. Lisaius at the White House, presidential appointments are made on the basis of ability rather than political affiliation. According to people close to the U.S. attorney’s office in Manhattan, however, Mr. Kelley was told upon his appointment as acting U.S. attorney that he would not be considered because of his rumored status as either an independent or a Democrat. A check of voter registration records shows that the only David. N. Kelley in the state with the same December birth date as the current U.S. attorney has been an enrolled Democrat since 1978.

Given Mr. Kelley’s experience, connections, and apparent suitability to the Bush Justice Department, the likeliest reason for a delay, some people close to the office said, could simply be that no one has gotten around to it.

“I think there’s inertia right now,” one former assistant U.S. attorney said. “That’s what I’ve heard. I think there’s inertia around the country.”

That might also explain why Mr. Kelley’s previous post as deputy U.S. attorney has gone unfilled for so long. A former deputy U.S. attorney under Mary Jo White, Shirah Neiman, who was thought to have wanted the top job herself at one time, declined to comment on the importance of the deputy’s job, except to say that she had managed to work “22 hours a day” in the post.

As for when – and if – a replacement will be nominated during the president’s second term, people close to the office said they are more uncertain now than they were last year. One former federal prosecutor predicted a decision would be made in weeks, while others said they have heard nothing on the job in months.

“Not long after Comey left, he was told he wouldn’t be considered,” one assistant U.S. attorney said of Mr. Kelley. “But then again, here we are.”