Advocates for criminal justice reform and others are lauding a three-way agreement between Gov. Andrew Cuomo and lawmakers on a bill that will create a commission to investigate misconduct by the state's district attorneys.

That celebration may be short-lived as the state's district attorneys are expected to challenge the legislation's constitutionality in court in the coming days. The president of the District Attorneys Association of the State of New York, Albany County District Attorney David Soares, said Cuomo's approval of the bill was “unfathomable,” and promised to file a motion for declaratory judgment to determine if the bill is constitutional.

“It is unfathomable that lawmakers would author and pass a bill that has numerous constitutional flaws and violates the separation of powers,” Soares said in a statement. “It is outrageous that the Governor would sign such a bill.”

Soares noted that Cuomo chose to sign the bill despite a warning from General Counsel Leslie Dubeck of Attorney General Barbara Underwood's office that the bill would likely not survive judicial review as written.

“As a result of today's events, DAASNY has little choice but to defend the constitution in court yet again—by mounting a vigorous challenge to the enactment of this misguided legislation,” Soares said.

The legislation was modified to address some, but not all, of Dubeck's concerns. She sent a memo to the governor's office last week outlining the potential constitutional challenges to the bill.

Cuomo said in his approval message with the bill that the legislation was too important to veto.

“The current bill, however, suffers from several flaws that have been identified by the State's judiciary, as well as the State's Office of the Attorney General, that would cause its undoing and would undermine the laudable goal sought to be achieved by its passage into law,” Cuomo said. “Despite these concerns, the importance of the overarching goal of the bill cannot be overstated and must not be ignored.”

The sponsors of the bill agreed to change the judiciary's role with the commission and the number of appointments given to each branch of government. A provision will also be included to protect active investigations by prosecutors from any intrusion by the commission.

The New York State Association of Criminal Defense Lawyers, which rallied with lawmakers to pass the bill during the final days of session in June, thanked Cuomo for his approval.

“NYSACDL thanks Governor Cuomo for doing the right thing and taking the final step to make the Commission on Prosecutorial Conduct a reality,” said NYSACDL President Robert Wells in a statement. “NYSACDL is proud to be one among numerous organizations and individuals who supported the Commission. We appreciate Governor Cuomo listening to our collective voice and look forward to further Criminal Justice reform in the years to come.”

The bill's sponsors echoed those comments after Cuomo's approval Monday. It's a rare moment for Sen. John DeFrancisco, R-Syracuse, who sponsored the bill in the State Senate. He's been an outspoken opponent of Cuomo in recent years, even mounting a short-lived gubernatorial campaign in January.

“There have been many cases of individuals who've been wrongfully convicted, and have served jail time, because of the misconduct of some prosecutors,” DeFrancisco said in a statement. “Despite the good work of most prosecutors, there must be a remedy against those who violate the law.”

Assemblyman Nick Perry, D-Brooklyn, sponsored the bill in the Assembly. He said in a statement Monday evening that the legislation was never intended to target prosecutors as a whole.

“It cannot be emphasized enough that this legislation was never intended to be an attack on our state's prosecutors who overwhelmingly serve with principle in a manner that we can be mostly proud, and I applaud them for their public service,” Perry said.

The state's district attorneys disagree. Queens District Attorney Richard Brown said in a statement that he will “vigorously support” the DAASNY litigation.

“I am deeply disappointed that the Governor has chosen to sign into law legislation creating a Commission on Prosecutorial Conduct,” Brown said. “That this legislation is patently unconstitutional, ill-advised and plagued by many practical flaws is beyond dispute.”

Nearly all of the Democratic candidates for state attorney general agreed last week the bill had flaws and should be changed to meet Cuomo's approval. New York City Public Advocate Letitia James, one of those candidates, said on Tuesday the commission was long overdue.

“As a former public defender I know that the vast majority of prosecutors are decent men and women committed to enforcing the law and ensuring that justice is done. I am also mindful of the immense power that every prosecutor has,” James said. “This commission balances the need to ensure that prosecutors have the ability to do their job, while maintaining the public trust in the integrity of our criminal judicial system.”

The legislation will take effect in January, which is when lawmakers will also approve the changes to the bill. It's unclear when the litigation from DAASNY will be resolved, but the commission is unlikely to begin its work before then.

Soares asked the state's prosecutors in a letter last week to decline any appointment to the commission until their motion is decided. That would leave the commission without about a third of it membership, leaving it essentially inoperable for the time being.