"It's not the preferable route," the judge said from the bench in a little-noticed court hearing in late 2012, "because whatever the outcome, the criticism will be, 'This is one person.' "

She seemed to believe that a jury of New Yorkers was best to decide the volatile issue of whether the department's practice violated the Constitution. The ruling of a single judge, she said, would be attacked as "not a verdict of the community."

Judge Scheindlin, of Federal District Court in Manhattan, ultimately presided over a nine-week trial last spring, followed by her landmark ruling against the city in August.

But ever since, she has found herself embroiled in just the kind of debate she had expressed wariness about.

She was abruptly removed from the case by a panel of appellate judges who pointedly questioned her neutrality; her ruling was thrust into legal and political limbo; and her reputation came under attack from city officials and newspaper editorial writers, seemingly emboldened by the appellate court's blunt critique.

Yet with Mayor Bill de Blasio's announcement that he plans to withdraw the city's appeal — he said on Thursday that there could be action "in the coming days" — the judge's ruling could take effect, setting up sweeping new oversight of the Police Department. It could also serve as a road map to a broad settlement of the stop-and-frisk dispute, if Mayor de Blasio seeks such a deal. Regardless of how the new mayor handles the case, it will offer an early measure of his approach to policing and civil liberties.

Unusual Spectacle

Full of biting recriminations and big headlines, the aftermath of the city's appeal was a spectacle. It stripped the federal courts of some of their usually staid facade, and it revealed, through documents and interviews, the machinations behind a case laden with political, racial and constitutional considerations.

Judge Scheindlin even took the unusual step of retaining a law professor who filed motions asserting that her rights had been violated.

"It's always unfortunate when the merits of an important case get overshadowed by the personalities of the judges, and that's what happened here," said Burt Neuborne, the law professor representing Judge Scheindlin.

But a former city lawyer says it was bias by Judge Scheindlin that overshadowed the merits. "It's a shame when the personality of the judge affects the outcome of the case," said Daniel S. Connolly, who represents former Mayor Rudolph W. Giuliani and Michael B. Mukasey, a former United States attorney general, in a brief supporting the city's position.

Judge Scheindlin's emergence as a polarizing figure in the litigation had its roots in a suggestion she made to plaintiffs' lawyers in court in 2007, during a hearing involving an earlier stop-and-frisk lawsuit, called Daniels v. New York.

The case, filed in 1999, challenged the stop-and-frisk tactics of an elite plainclothes unit responsible for the fatal shooting of an unarmed immigrant named Amadou Diallo.

As part of a settlement, the Police Department agreed to a written policy against racial profiling.

But in December 2007, days before the judge's authority over the case was to expire, the Daniels lawyers returned to court, saying that the department, with soaring numbers of police stops, had violated the settlement.

Judge Scheindlin told the lawyers that the issue might be better addressed by bringing a new case. "If you got proof of inappropriate racial profiling in a good constitutional case," she said, "why don't you bring a lawsuit?" The plaintiffs could designate the suit as "related," she said, adding, "I would accept it as a related case."

The reference was to a rule directing lawyers to route a lawsuit to a judge who is already hearing a case with similar facts. The "related case" rule is meant to streamline litigation but also bypasses the random assignment process.