Six years ago, with crime rates at historic lows and Democratic progressivism on the rise, New York State began requiring prosecutors to turn over reams of evidence to defense lawyers well before a trial.

The goal was to level the playing field for criminal defendants, who often took plea deals without understanding the full scope of the case being built against them.

But many of the state’s district attorneys say that their offices have struggled to comply with the new requirements and blame them in part for an increase in case dismissals, which rose 22 percentage points in New York City.

They have urged state leaders to consider changing the so-called discovery rules, and have won over a powerful ally, Gov. Kathy Hochul.

The governor, a Democrat, is backing a measure that would ease the consequences for prosecutors if they do not share evidence in a timely manner. Her proposal would also let them redact information without a judge’s permission.

Ms. Hochul has said her plan will improve processing times and solve the problem of dismissals “based on technicalities that can prohibit justice to victims and the people of the State of New York.”

Ms. Hochul’s embrace of the issue reflects a broader shift in the priorities of politicians in New York and across the nation. In recent elections, Republicans have made gains by tarring Democrats with accusations that they are soft on crime. New York’s leaders have sensed the shifting winds and grasped for ways to show voters they are taking their public safety concerns seriously. Not only prosecutors but liberal power brokers like the Rev. Al Sharpton back Ms. Hochul’s ideas.

“There is a swing back toward pragmatism on how we approach the criminal justice problem,” said Lee Kindlon, a Democrat and Albany’s district attorney, who was a defense lawyer before taking office in the fall. “The politics have changed.”

Ms. Hochul’s requests, which were included in her executive budget proposal this year, have alarmed defense lawyers. Her efforts would return New York to the days when prosecutors would face no consequences for waiting until the day of trial to share evidence, depriving defendants of the chance to mount an informed defense, they said. Prosecutors, they say, will revert to withholding material.

Eli Northrup, policy director of the criminal defense practice for the Bronx Defenders, disputed prosectors’ arguments, saying that cases “can’t get dismissed on a ‘technicality.’”

“I understand the broader complaint of cases shouldn’t go away,” Mr. Northrup said. “But it’s the responsibility of a government that is bringing charges against somebody to bring documents.”

Changes to the discovery law will be part of broader budget negotiations among the leaders of the State Senate and Assembly, who are both Democrats and have expressed discomfort with some changes. Both chambers recently left the government’s proposals out of their budget counteroffers.

Andrea Stewart-Cousins, the Senate majority leader, said they should discuss the subject later outside budget talks. Carl Heastie, the Assembly speaker, said he was open to changing the law but was concerned about giving prosecutors total discretion.

“We would rather let the judge be the actual arbiter,” Mr. Heastie said.

Broad changes to the criminal justice system were approved in 2019. At the time, New York was one of 10 states that allowed prosecutors to wait until the eve of trial to hand over crucial evidence.

The new discovery law was a major win for defendants, who had helped draft the measure. But prosecutors say they now have to devote hundreds of hours to collecting materials they say are only tangentially related to a case.

Prosecutors have said that judges regularly dismiss cases because of minor mistakes in supplying evidence, a process known by the legal term discovery. The remedy should be proportional and not result in automatic dismissals for violating the Constitution’s speedy trial requirement, they have said.

Only 5 percent of misdemeanor and felony cases in criminal court in New York City were dismissed because of speedy trial violations in 2019, according to state court data. In 2024, that number had jumped to 31 percent.

Prosecutors insist that their goal is not to roll back the 2019 law.

Alvin L. Bragg, the Manhattan district attorney, said that he supports lawmakers making “common-sense adjustments to the statute to protect victims of crime.” The changes would keep the state’s laws “the most open and transparent discovery laws in the nation,” he said.

Darcel Clark, the Bronx district attorney, recently told lawmakers that she “championed the transformation.” Prosecutors, she added, want “minor revisions to help for the things that were the unintended consequences.”

Amanda Jack, policy director at the Legal Aid Society, said that the governor’s support, along with that of New York City’s police commissioner, Jessica Tisch, and mayor, Eric Adams, has given the prosecutors’ mission momentum.

Ms. Hochul said this month that unease about safety changed people’s attitudes about discovery laws “dramatically.”

“I am just trying to solve the problem,” she said, adding that “the pendulum swings, and you start seeing the impact.”