Cyrus R. Vance Jr., the Manhattan district attorney, seemed preoccupied when he sat down with two reporters last Monday. He already knew what the world would soon learn: his marquee prosecution — the sexual assault case against Dominique Strauss-Kahn — was falling apart. Privately, his aides had told him that they had discovered grave problems with the accuser’s credibility.
The interview began, but before Mr. Vance was asked a question, he offered an unsolicited defense — not just of the Strauss-Kahn case, but of his overall stewardship.
“Ultimately,” he said, “the success of a D.A.’s office— and of a D.A. — is measured not in individual cases, but over time.”
“The cases you don’t read about,” he added, “define what the job of a D.A. really is.”
But that job has grown increasingly tumultuous. Since Mr. Vance took over 18 months ago, morale in some parts of the district attorney’s office has begun to sag, in part because of his firing of some prosecutors. Relations with one of the office’s key partners, the Police Department, have grown tense at times, with the two agencies competing over many issues, including control of anticrime initiatives, according to officials on both sides.
Mr. Vance’s predecessor, Robert M. Morgenthau, who became the pre-eminent prosecutor in the country while holding the post for 35 years, was once a close ally of Mr. Vance’s, providing crucial support for his election in 2009.
Now, Mr. Morgenthau, 91, rarely if ever speaks to Mr. Vance.
Mr. Morgenthau has apparently become displeased with Mr. Vance’s management style and his revamping of the staff that Mr. Morgenthau put together, according to people who know both men well. Mr. Vance’s supporters attribute the criticism of his tenure to people who are unsettled by his efforts to reinvigorate and modernize an office that his supporters say had stagnated under Mr. Morgenthau. They pointed out that only after Mr. Vance became district attorney were prosecutors given smartphones.
Still, the second-guessing of Mr. Vance’s leadership has intensified in the wake of a string of courtroom losses that culminated in the startling events last week, when prosecutors revealed their concerns about the honesty of the hotel housekeeper who accused Mr. Strauss-Kahn of sexual assault in May.
Even Gerald L. Shargel, a Manhattan defense lawyer who served on the finance committee for Mr. Vance’s 2009 campaign, questioned how the case had been handled.
“What’s most curious is hearing the line prosecutors saying early on that they had a strong case, a very strong case,” Mr. Shargel said. “Obviously, they hadn’t looked very hard. I have enormous respect for Cy as a prosecutor, but this is like a series of bad dreams.”
A judge in Manhattan freed Mr. Strauss-Kahn from house arrest on Friday, and the case against him appeared to be collapsing.
In the weeks before that, Mr. Vance’s office did not win rape convictions against two New York police officers accused of sexually assaulting a drunken woman (the officers were found guilty of lesser charges). And the most significant terrorism charges were dropped against two men accused of planning attacks against synagogues in the city, though serious counts remain.
Some of the most pointed complaints about Mr. Vance are emanating from the district attorney’s office itself, according to numerous interviews with prosecutors and other officials. They spoke on the condition that their names not be used, saying they feared reprisals.
Several said they worried that cases were often pursued with an excessive focus on whether they would generate publicity. Some said Mr. Vance had taken away the discretion of midlevel prosecutors, sometimes to the detriment of cases.
Those two issues, some prosecutors said, contributed to the difficulties in the case against Mr. Strauss-Kahn, the former head of the International Monetary Fund who had been considered a leading candidate for the French presidency.
After Mr. Strauss-Kahn’s arrest, the district attorney’s office faced the question of whether to ask a judge to keep him in custody.
To do so, the office had to obtain an indictment within five days. The alternative was to agree to a bail package so that prosecutors could take their time investigating the case before deciding whether to indict, according to four people briefed on the matter.
In the end, Mr. Vance chose a quick indictment, drawing criticism that he moved before he knew of the accuser’s background.
Prosecutors have said in court that they decided to seek the indictment and to keep Mr. Strauss-Kahn in custody to avoid the possibility of Mr. Strauss-Kahn’s fleeing the country.
The case also unfolded as a rift had already developed between Mr. Vance and the chief of the office’s sex crimes unit, Lisa Friel. She stepped down last week under circumstances that were not entirely clear. It did not appear that her decision was directly related to the Strauss-Kahn case.
Early on, Mr. Vance took the case away from the sex crimes unit and gave it to two other experienced assistant district attorneys.
Some people in the office said that decision hurt the office’s handling of the case because those prosecutors were not as familiar with the types of problems that sex crimes prosecutors routinely face: a victim with a troubled background; a he-said, she-said story.
With an experienced sex crimes prosecutor, an official in the office said, “some of these very things that have come up, or even some things that might have come up during deeper examination by people who were experienced in this, might have come up faster.”
Mr. Vance’s top aides said that the outcome of the case would have been the same if it had been handled by the sex crimes unit, and that some of the office’s best prosecutors were on the case.
On Friday, after Mr. Strauss-Kahn was freed from house arrest, Mr. Vance would not address the criticism surrounding the prosecution’s conduct. The office has not dropped the charges, though Mr. Strauss-Kahn’s lawyers are demanding that it do so.
Mr. Vance does not appear entirely comfortable in the spotlight, and still seems to be adjusting to the mantle of his office. When he went before reporters on the steps of the Manhattan court on Friday, the first thing he did was introduce himself, underscoring the contrast with his predecessor, who was so well-known that he needed no introduction.
Mr. Vance then read a statement, saying that he had done the proper thing “ethically and legally” by allowing Mr. Strauss-Kahn to be freed. “As prosecutors, our duty is to do what is right,” he said. He would not answer questions.
Mr. Strauss-Kahn’s lawyers immediately praised Mr. Vance’s integrity and courage. But Kenneth P. Thompson, a lawyer for the accuser, assailed Mr. Vance, saying that even if there were problems with the woman’s statements about her personal history, there was ample evidence that a sexual assault had occurred.
“Our concern is that Manhattan district attorney Cy Vance is too afraid to try this case,” Mr. Thompson said. “We believe that he is afraid that he is going to lose this high-profile case.”
Asked later about that statement, Mr. Vance’s senior aides declined to respond. But Daniel R. Alonso, Mr. Vance’s top deputy, praised Mr. Vance’s oversight of the office.
“He is extremely respectful of multiple and divergent points of view, and he wants to hear lots of people’s opinions before he makes a decision,” Mr. Alonso said. “Once he does that, I would describe him as decisive. He’s not afraid to make a decision.”
Mr. Vance, 57, who is married with two children in college, came into office with high expectations. He had a famous name — his father was secretary of state under President Jimmy Carter — and the support of much of the city’s Democratic political establishment.
Mr. Vance agreed to be interviewed about his tenure last Monday just as the Strauss-Kahn case was falling apart, though he did not reveal directly what he knew.
He wore a crisp white shirt during the interview in his eighth-floor office, which is filled with modern art and pictures of his family. By turns, sober, thoughtful and defensive, he often spoke with both hands slicing the air in front of him.
The office handles roughly 110,000 cases a year, he noted.
“I think the tough part of this job, the tough part of running an office this big,” he said, “is to try to do the best job possible representing the interests of victims and defendants over the course of the huge volume of cases that we are responsible for.”
Mr. Vance said he made no apologies for exerting more control over mid-level prosecutors.
“To be frank, some discretion may have been taken away from them,” he said, adding that closer monitoring was important for maintaining uniform and fair prosecutorial practices.
He also suggested that he was wary of being constantly compared to Mr. Morgenthau, his predecessor.
“At 57 years old, having been here 18 months, we are moving in a direction,” Mr. Vance said. “I think it is an issue I long ago stopped focusing on in my own head, and you shall decide when you choose to focus on something else.”
Mr. Morgenthau declined to comment.
As the week ended, friends and supporters of Mr. Vance’s heatedly discussed what the Strauss-Kahn case meant for his political future. They said the case had placed Mr. Vance in an unenviable position: On the one hand, the accuser has been discredited by her misstatements and apparent connections to criminal activity. At the same time, they said, physical evidence suggested that some kind of nonconsensual encounter probably did take place.
Before the recent revelations, Mr. Vance had begun putting together a campaign for re-election in 2013, holding a breakfast for donors in May and sending out fund-raising e-mails. He marched, along with members of his office, in the gay pride parade last month, and had assembled a small but skilled political team.
His supporters were, before his current troubles, mostly full of praise for his tenure, noting that he had created innovative programs like a conviction integrity unit, which examines troubled prosecutions for mistakes.
Now, some of those supporters are wondering what will happen next.
“It’s a little early to know exactly what the impact of all of this will be,” said Barry Scheck, a lawyer and a founder of the Innocence Project, who advised Mr. Vance on the creation of the conviction integrity unit. “But if, in fact, the office winds up deciding that the case shouldn’t have been made in the first place and brought exculpatory evidence to the defense in a prompt, appropriate way, that’s a good thing,” Mr. Scheck said.
Some friends conceded that Mr. Vance was not a seasoned politician who knew how to do damage control.
Eliot Spitzer, the former governor, said the unanswered questions in the case — “Was there sufficient skepticism? Should they have withheld judgment until more was known?” — had to be balanced against the fact that Mr. Vance had acted properly once he determined there were problems. “It’s impossible at first to push back against stories like this,” Mr. Spitzer said. “It will have an impact, but 10 thousand other cases, even high-profile cases, will emerge.”
This article, "," first appeared in The New York Times.