Voters in Montana will decide in November whether to enshrine a right to abortion in the state Constitution, joining eight other states with similar citizen-sponsored questions on their ballots.

Montana’s secretary of state sent an email late Tuesday to the coalition of abortion rights groups sponsoring the measure, certifying that they had collected enough valid signatures to place it on the ballot. The coalition had submitted more than 117,000 signatures, nearly double the 60,039 required and the most submitted for a ballot measure in Montana history.

And in Arizona — which, like Montana, was facing a Thursday deadline to certify its ballots — the state’s Supreme Court rejected an appeal late Tuesday from anti-abortion groups trying to strike a similar measure that the secretary of state there had approved last week. The justices, all appointed by Republicans, said that their decision did not signal support for the measure, only that they did not agree with the technical objection raised by the anti-abortion groups about the language used on ballot petitions.

National Democrats and abortion rights groups are pouring money into ballot measures in both states in the hopes that they can drive turnout to help the Democrats running for the Senate, where the party holds a razor-thin majority. In Montana, Senator Jon Tester is perhaps the party’s most endangered incumbent.

Abortion remains legal in Montana until viability — the point when a fetus can survive outside the uterus, generally around 24 weeks of pregnancy — because of a 1999 state Supreme Court decision that said the right to privacy in the state Constitution included a right to “procreative autonomy.”

Advocates say the measure is necessary to prevent future members of the court, who are elected, from reversing that decision. And the state’s Republican governor, Greg Gianforte, and the Republican-controlled Legislature have repeatedly tried to ban or restrict abortion.