HANOVER — The Selectboard has postponed a vote on a proposed ordinance intended to protect undocumented immigrants in Hanover after a last-minute change led to a heated debate over legal concerns.

Kira Kelley, an attorney who’s been working with activists and a group of Hanover residents to advance the policing-related ordinance, said the change adds legal language to the body of the proposal that “undermines” the rest of the measure.

But Town Manager Julia Griffin argued the change was a relatively minor adjustment in wording.

Selectboard members decided on Monday night to table the vote on the “Fair and Impartial Policing” ordinance in order to give town attorneys, Griffin and supporters of the original proposal time to come to an agreement on the language before the next meeting.

The proposed ordinance would prohibit Hanover police officers from asking about a person’s citizenship status or from sharing citizenship information with federal authorities.

Opponents of a similar ordinance in Hartford argued that it violates a federal law that says local police must share immigration information with federal authorities. But supporters of the Hartford ordinance said the federal law itself is unconstitutional, and the Selectboard in Hartford recently approved it on a 6-1 vote after an advisory measure won strong approval at Town Meeting.

Questions over how the so-called “welcoming” ordinance interacts with that federal law are at the core of the disagreement in Hanover as well.

A paragraph in the draft ordinance that says it “may not override any state or federal law” was originally contained in the “Declaration of Purpose” section.

But on Monday, the town’s attorneys moved the paragraph to its own section within the body of the ordinance — a decision that Asma Elhuni, one of the activists pushing the measure in several Upper Valley towns, said makes the language more legally binding.

“The declaration of purpose … is not a legal mechanism,” Elhuni said in a message Tuesday. “Moving the language from the preamble to the body of law has significant legal meaning, which includes making the ordinance possibly useless.”

During Monday’s meeting, Kelley compared the new section to a controversial “savings clause” proposed in the similar Welcoming Hartford ordinance. The Hartford clause, which would have explicitly said police are not barred from sharing immigration information, was dropped by Hartford after outcry from activists.

While the new section of Hanover’s ordinance wasn’t expressly called a “savings clause” it would allow town employees to “disregard” any part of the ordinance that they think might conflict with federal law, including sharing citizenship information, Kelley said.

“The only way for this ordinance to have weight is for it to conflict with (the federal law and) … to create a firewall between U.S. Immigration and Customs Enforcement and local law enforcement,” she said in an interview following the meeting.

Other activists and supporters of the original measure opposed the change to the proposal for similar reasons Monday, arguing that it nullifies the ordinance.

“It will strip the essence of our work and the goal of our work,” said Kristina Wolff, a Dartmouth researcher and one of the Hanover residents organizing for the ordinance.

But Griffin argued Monday that the new proposal is not that different from the one agreed upon when she met with proponents on Friday.

“I’m angry, quite frankly, because when we left the conversation Friday we were all set. So what happened over the weekend?” she asked.

She went on to say that the only difference between Friday’s ordinance and Monday’s copy is that the town attorney “gave the paragraphs their own section.”

“(It’s) virtually the same wording, but just a different location,” Griffin said in an email Monday.

Selectboard members urged supporters and town officials to find a compromise before the next meeting on April 20, but many acknowledged their annoyance that they wouldn’t vote on the measure Monday.

“It’s very disappointing because we thought we had this all wrapped up,” board member Athos Raissas said Monday.

Griffin said the groups would meet again, but added that she thinks they might have a fundamental difference of opinion that will make it hard to find common ground.

“I don’t think it’s possible to come to an agreement with them on this issue,” she said.

The ordinance will likely come back up for a vote again at the Selectboard meeting on April 20. If it’s rejected by the Selectboard then, activists won’t be able to get it on the warrant for Town Meeting, now scheduled on June 23, because Tuesday was the last day to submit a petition.

Similar immigration measures were recently passed in Hartford, Lebanon and Norwich.

The Norwich Selectboard plans to vote on that town’s ordinance Wednesday.

Anna Merriman can be reached at amerriman@vnews.com or 603-727-3216.