House lawmakers on Wednesday voted to put a constitutional amendment before voters that would define “person” as “beginning at the stage of fertilization or conception.”

If passed in 2026, the proposal would likely conflict with CI-128, the constitutional abortion rights amendment approved in November. During a Tuesday debate on the measure, the sponsor of House Bill 316, Rep. Lee Deming, R-Laurel, said that he believed voters may have “some buyer’s remorse” about the recently passed measure. 

“To be honest with you, I’m not sure that the people who voted on CI-128 really understood what they were voting for,” Deming said. “I want to give these people of Montana another opportunity.”

CI-128, which bars state government from restricting pre-viability abortions, passed by a 16 percentage point margin.

Deming’s proposed amendment will advance to the Senate for consideration but is unlikely to pass out of the Legislature. Constitutional amendments introduced by lawmakers must have the support of two-thirds of the entire branch, or 100 votes from the two chambers combined. 

The House’s party-line vote Wednesday gave HB 316 the support of 58 Republican lawmakers. That number means that 42 out of 50 Senators would have to vote for the bill in order for it to pass, a high bar for a chamber with 18 Democrats.

The personhood amendment is one of the few abortion-related bills that have been introduced this session. Other efforts to curb medication abortion and prohibit abortion “trafficking” inside and outside of Montana’s borders failed to advance. 

Two of those proposals were tabled in committee, in part because of concerns from Republican lawmakers about conflicts with CI-128. A separate bill failed to pass a vote on the Senate floor. Another measure to allow for paternity testing and child support payments during pregnancy, which also included language about life beginning at conception, also failed to advance out of committee. 

Supporters of HB 316 have acknowledged that the measure runs counter to what voters expressed several months ago at the ballot box. But lawmakers who spoke in favor of the amendment on the House floor this week said it aligned with their deeply held beliefs about protecting fetal life. Several likened their commitment  to the issue to the long fight for the abolition of slavery in the United States.

“In a few years or decades, I believe we will look back on the error of not recognizing personhood for babies. Please join me in voting yes on this bill and may history look favorably upon your vote today,” said Rep. Greg Overstreet, R-Stevensville.

Multiple Democrats and one Republican spoke against the measure on the floor. Some raised concerns about who would be able to assert the rights of a fetus, and whether the will of the state, an abusive partner or potential grandparents could hamstring the medical decisions of the pregnant person. 

“I think that one of the serious unintended consequences of an initiative like this is that it creates a legal pathway for more of that sort of coercive control,” said Rep. SJ Howell, D-Missoula. “Control over a woman by somebody who does not have her best interests at heart.”

If it became part of the state Constitution, opponents said, the amendment could also interfere with the provision of birth control, miscarriage management and in vitro fertilization processes for people trying to become pregnant. 

Members of the public who testified against the bill during its first hearing before the House Judiciary Committee in early February raised similar points. During that discussion and the recent floor debate, Deming acknowledged that the proposal would impact IVF access in Montana, a fertility treatment he said he would otherwise support if not for the disposal of unused embryos. 

Proponents reiterated that the bill promoted more foundational values. 

“We’re ignoring a basic truth that nobody seems to — everybody wants to seem to step around it,” said Rep. Zack Wirth, R-Wolf Creek. “Women give life. Men protect life. There’s no other truth more basic.”

Other opponents rebuked lawmakers for, in their eyes, disregarding what Montana voters decided in November. 

“The voters have weighed this issue. They have voted. You didn’t like what they did, so now you, as the Legislature, are deciding you’re going to override their vote,” said Rep. Pete Elverum, D-Helena. “Just stop.”

Rep. Sherry Essmann, R-Billings, was the only Republican to vote against the measure Tuesday, citing her reluctance to further change the Montana Constitution with a contradictory amendment.

“We’re doing nothing but confusing our voters. We asked them last time if they were for or against abortion, and now we’re gonna give them even more confusing language that makes them wonder, ‘Well, now what does this mean?’”

During her questioning about the bill’s intent, Essmann asked Deming whether he thought Montana voters were not smart enough to understand what they were voting on last year. Deming said he thought the electorate was “plenty smart enough,” but suggested that voters may have been misled by some of the messaging by CI-128 proponents.

Essmann’s opposition did not hold for the bill’s final House vote. The measure passed on Wednesday 58-41. It has not yet been scheduled for a hearing in the Senate.