Gov. Janet Mills won’t sign a bill passed by Maine lawmakers to limit local law enforcement’s ability to work with federal immigration authorities, likely leaving the legislation in limbo until next year.

Mills will wait to take action until the next legislative session, when she will either veto the measure or allow it to become law without her signature.

“The Governor understands the motivation behind the legislation,” Mills spokesperson Ben Goodman said in an email Tuesday. “She believes, however, that the legislation as enacted — which is billed as attempting to provide clarity to Maine law enforcement — does the opposite. The bill is both overly broad and confusing, as it establishes a complicated legal regime of the type of interactions that are or are not permitted with federal law enforcement.”

The bill, LD 1971, was approved 75-73 in the House of Representatives and 20-14 in the Senate last month, and was among the most controversial of the legislative session that ended last week.

Mills did not act on the bill before the Legislature adjourned, removing her ability to issue a veto until the next session. She still had 10 days after enactment to sign the bill into law, but that deadline passed Monday.

As a result, the measure will be held until the Legislature returns for at least three more days, at which point the governor may veto the bill or allow it to become law without her signature. The next scheduled session will begin in January, although a special session could be called before then and trigger action on the bill.

Rep. Deqa Dhalac, D-South Portland, the bill’s sponsor, did not respond to voicemail messages or an email asking about the status of the bill and her reaction to it being held.

But Democratic leaders said they want to work with the governor to address her concerns and find a way forward for the bill.

“Here in Maine, we continue to see and hear horrifying stories of people being detained without due process — including folks who are legally present in our state,” said House Speaker Ryan Fecteau, D-Biddeford, and Senate President Mattie Daughtry, D-Brunswick, in a written statement. “This bill seeks to ensure that all Maine people have access to justice and due process.

“Due process is not some sort of aspiration. It is a cornerstone of our nation’s Constitution. We are committed to working with the Governor to address her concerns with the bill and find a path forward that reinforces fidelity to these core American principles.”

The bill was one of two that came forward this year aimed at limiting local and state collaboration with federal immigration authorities.

Both measures followed President Donald Trump’s efforts to fulfill a campaign promise to conduct the largest mass deportation effort in American history. Trump originally said he would focus on violent criminals in the country illegally, but his administration has been detaining people who are not accused of crimes, and in some cases deporting them without due process, sometimes in violation of court orders.

The second bill, LD 1259, which would ban agencies from entering into contracts with federal immigration enforcement authorities, was carried over to the next session.

Dhalac’s bill would prohibit state, county and local law enforcement officers from investigating, detaining or searching a person solely for immigration enforcement purposes.

It also would not allow local officers to be placed under the supervision of federal authorities for the purpose of working on immigration enforcement, or allow local law enforcement to use federal immigration officers as interpreters.

The bill would still allow local entities to participate in various task forces with federal agencies and to assist federal agents in criminal investigations, including executing warrants and sharing information on suspected criminal activity. Additionally, federal immigration agents could interview someone in custody with a court order.

If Mills does ultimately allow the bill to become law, it will likely be many months before it takes effect since the Legislature is not scheduled to come back until January. Bills that are held and become law take effect following the session they were held over to, typically taking effect 90 days after adjournment.

The bill generated significant debate in both the House and Senate after drawing support from immigrants rights advocates at a public hearing in May. Maine State Police testified against the bill at the time, saying it was too restrictive and would significantly reduce their ability to work with federal authorities, although the final version of the bill was amended to clarify some of its provisions.

It passed the Legislature largely along party lines, with two Democrats, Stephan Bunker of Farmington and Dani O’Halloran of Brewer, joining Republicans in opposing the bill during the final House vote, while Sen. Rick Bennett, R-Oxford, joined Democrats in supporting it in the Senate.

Republicans accused Democrats of trying to create a sanctuary state, which they said would make Maine a magnet for people who are in the country illegally, jeopardize federal funding and compromise public safety. A fiscal note attached to the bill said it could risk up to $14 million in grant funding related to law enforcement work with immigration enforcement efforts.

Democrats argued that the bill would ensure Maine’s law enforcement community can use its resources to focus on criminal activity and maintain trust with members of the immigrant community, many of whom, they said, are not going to work or school, or reporting criminal activity to police out of fear of deportation.

“Currently, local law enforcement is diverting Maine’s public safety resources to engage in civil immigration enforcement across our state, which is causing widespread and growing harm,” Dhalac said in testimony to a legislative committee in May.

“The results include a loss of public trust and a loss of public safety information as people are deterred from reporting crimes, including domestic violence, asking for police assistance, serving as witnesses in criminal cases and more.”

She said the bill clarifies the responsibilities of local law enforcement when it comes to immigration matters. “Specifically, it ensures that our local and state law enforcement agencies can focus on their primary mission: safeguarding our communities and upholding state laws,” she said.