Helena, Montana - Montana on Tuesday became the latest state to add abortion rights to the November ballot, allowing its electorate to decide whether they back a constitutional change to protect access to the procedure.

Abortion rights have become a key electoral issue and a rallying cry for Democrats since the nationwide right to the procedure was struck down by the conservative-dominated US Supreme Court in 2022.

The Montana initiative, if passed, "would prohibit the government from denying or burdening the right to abortion before fetal viability," Montana's Secretary of State's office said on its website.

The state's government would also not be allowed to deny or impede access to an abortion in cases where a medical professional indicates the pregnancy poses a threat to a mother's life.

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"The initiative would prevent the government from penalizing patients, healthcare providers, or anyone who assists someone in exercising their right to make and carry out voluntary decisions about their pregnancy," the Secretary of State's office added.

The initiative follows a similar move in Arizona earlier this month and makes Montana the eighth state to put abortion protection on its November ballot, according to US media.

Democrats are seeking to make abortion rights a major issue in the election, especially in key swing states such as Arizona, where President Joe Biden defeated Republican Donald Trump by just 10,000 votes in 2020.

Vice President Kamala Harris has established herself as a leading advocate of abortion rights as she prepares to take on Trump in the November elections.

Many Republican-led states quickly moved to restrict or outright ban the procedure following the 2022 Supreme Court ruling.

A petition to put the issue on the ballot in Montana garnered 81,000 signatures, or over 10% of registered voters, according to NBC Montana.

Several other states have added abortion access ballot measures in the November election, including Arizona, Colorado, Florida, Maryland, Nevada, New York, and South Dakota, with several others still pending.

Some 21 other states have set stricter standards for abortion since the fall of Roe v. Wade, ranging from full bans to earlier gestational limits.