Gov. Charlie Baker has returned to the Legislature landmark legislation that would impose new accountability standards on police, proposing a handful of amendments Thursday that he hopes Democrats will compromise with him over, but making clear he's not afraid to veto the legislation if lawmakers resist those changes.

Baker, a Republican, has faced mounting pressure from both sides of the policing debate since the Legislature finalized its oversight bill over a week ago. Criminal justice reform advocates have urged him to sign it, while police unions have called it an attack on the men and women who wear a badge.

In an interview with the News Service, the governor said he was willing to make concessions, including accepting a civilian-controlled licensing board and limits on qualified immunity for police officers, but drew a line on several key issues.

Baker said he would not sign a bill that, in any way, bans police from using facial recognition systems to solve crimes but believes concerns over biases in such software systems need to be studied further. He also said the development of training programs for police should not be handed over to a civilian-controlled commission, but should be managed by law enforcement personnel within the executive branch.

"This is about making compromise and I'm ready to do that on almost everything with respect to improving accountability for law enforcement. But there are parts of this bill that were never part of that conversation about accountability that I can't support," Baker said.

A veto could force the Legislature to revisit the issue from scratch in the next session, which begins on Jan. 6. Democratic leadership in the House could not muster a veto-proof majority to pass the bill last week, voting 92-67 in favor of a conference report that could not be amended on the floor.

The 28-12 margin in the Senate was also razor thin, leaving Democrats able to lose just one vote to be able to override the governor.

Asked if he was willing to risk losing the momentum behind the bill this year, Baker said he hoped the "deference" he was showing to the Legislature by limiting the scope of his proposed changes would entice them to compromise.

"I think the Legislature wants this accountability bill passed and signed just as badly as we do and we tried very hard here to focus on a very small number of things we thought were important," Baker said.

The Legislature last week sent Baker a compromise bill to create a new Peace Officer Standards and Training Commission, which would make Massachusetts one of the last states in the country to have a board in charge of licensing law enforcement officers.

The issue became a focal point for Beacon Hill following the killings of George Floyd and Breonna Taylor, whose deaths at the hands of police sent waves of demonstrators into the streets of Boston and other cities to protest police violence.

That POST Commission would have the authority to decertify police officers for violating a person's right to bias-free policing or using excessive force, and the bill would put severe restrictions on the use of chokeholds and no-knock warrants.

Baker said he supports all of those measures.

"We are really anxious to set up a system to license and delicense police, which we believe is a big missing link in our statutory framework," he said.

The governor also said he was willing to support an independent, nine-member POST Commission compromised of just three law enforcement officers and six civilians, despite his own bill in June that recommended an almost evenly-split board be put under the umbrella of the Executive Office of Public Safety. The composition of the commission has been a point of contention for police unions.

The governor is recommending is that one of the three police officers on the panel - the officer below the rank of sergeant - be a labor union representative chosen from a list prepared by the Massachusetts Law Enforcement Policy Group.

Baker said he could "live with" another controversial section of the bill that would expose law enforcement officers who have been decertified for misconduct to civil lawsuits by removing their qualified immunity protection for actions taken on the job.

"I want to sign a bill and I'm willing to let a lot of things that were not a part of our legislation become a part of this package to get this done," Baker said, when asked about qualified immunity.

The sticking points, however, center around access to facial recognition technology, police training and his administration's ability to implement the law.

"I'm not going to sign a bill into law that bans facial recognition. I'm not going to sign a bill that puts people, by law, in charge of training police officers that are not law enforcement, and I'm not willing to take that activity out of the executive branch," Baker said.

The restrictions on the use of facial recognition were defended during debate by Democrats like Sen. Cythia Creem of and Rep. Dave Rogers, who said the RMV database was being used by police without warrants.

"The state is using powerful surveillance technology without regulation or oversight. This technology has been proven to misidentify people of color and women and it is so important that we take this step today," Rogers said in July.

The bill the Legislature passed would allow law enforcement to get a warrant to access the RMV system, or ask the RMV to help in emergencies. But governor believes facial recognition software can be an important tool in solving crimes, saying that he knew of two cases involving a child rapist and an accomplice to double murder that were solved with the help of the technology.

Baker is proposing to expand the scope of a study into the use of facial recognition, while at the same time stripping the bill of restrictions that ban all agencies except the Registry of Motor Vehicles from using any software that captures biometric data.

"We bulked up the commission that was established by the bill, but I'm not willing to get rid of it when it is a tool that can make a difference," Baker said.

Baker also proposed to remove police training from the purview of the POST Commission, and to restore the Municipal Police Training Committee to its current location within the executive branch.

"We need to make training better and that needs to be done within the context of the executive branch and with the cooperation of cities and towns," Baker said.

Baker also asked that the effective date for all organization changes in the bill be pushed out to the start of the new fiscal year on July 1, 2021 to give officials time to set up the new commission, and he said in the coming days he would be filing legislation to make funding available for the POST Commission to do its work.

"This is going to be expensive and the fact that there are no resources there I think is something we need to resolve," Baker said.

One of the other amendments offered by the administration would add to the definition of bias-free policing to make clear that police may consider a person's race, ethnicity, sex, gender identity or other traits as long as it was for a non-discriminatory reason or because those factors were an element of a crime.

Finally, Baker is recommending that police departments be given a finite amount of time to complete internal affairs investigations into police misconduct before the POST Commission takes control of an investigation, addressing some of the due process concerns raised by police and lawmakers.

"I do not believe that our amendments negatively affect the legislative vision for creating accountability," Baker said, adding, "I'm really excited that we're close to making this happen."