The Arizona Senate is expected to vote on Wednesday to repeal the state's near-total ban on abortion, which dates back to 1864 and was recently upheld by the state's Supreme Court. The historic vote comes after the state House narrowly approved the repeal last week, with three Republicans joining all 29 Democrats in the chamber to advance the measure.

If the bill passes the Senate, it will head to the desk of Democratic Gov. Katie Hobbs, who is expected to sign it into law. However, even if the repeal is successful, it may not take effect immediately due to provisions in the Arizona state Constitution that delay the implementation of repealed laws until 90 days after the legislative session concludes.

The 1864 law, which predates Arizona's statehood and was codified in 1901 and again in 1913, bans nearly all abortions from the moment of conception, with an exception only to save the woman's life. It also imposes prison terms of two to five years for doctors and others who aid in abortions, making it one of the most stringent abortion bans in the country.

The law had been blocked by the 1973 Supreme Court decision in Roe v. Wade, which granted the constitutional right to abortion. However, after Roe was overturned in 2022, the state's Republican-appointed Supreme Court justices suggested that the 1864 ban could be reinstated, placing enormous pressure on Arizona Republicans from both conservatives who support the ban and swing voters who oppose the extreme measure.

In the closely divided Senate, Democrats have secured the support of two crucial Republican votes needed to pass the repeal. State Sens. Shawnna Bolick and T.J. Shope are expected to join Democrats in voting to overturn the ban, reflecting the growing political pressure surrounding the issue in the battleground state.

If the repeal is successful, Arizona's abortion policy would likely revert to a 15-week ban passed in 2022, which includes exceptions for medical emergencies but not for cases of rape or incest. However, abortion rights advocates are pushing for a ballot measure in November that would enshrine the right to abortion in the state's constitution, effectively undoing both the 1864 ban and the 15-week ban.

The proposed constitutional amendment would create a "fundamental right" to receive abortion care up until fetal viability, typically around the 24th week of pregnancy. In the weeks since the 1864 ban was reinstated, the Arizona for Abortion Access effort has seen its volunteer base grow from about 3,000 to more than 5,000, underscoring the galvanizing effect of the issue on voters in the key swing state.

Republican lawmakers, meanwhile, are considering putting one or more competing abortion proposals on the November ballot, including a 14-week ban and a "heartbeat protection act" that would prohibit abortions after six weeks of pregnancy. However, no such measures have been introduced yet.

The continuing saga has raised the stakes for both parties in Arizona, a state that historically leaned Republican but backed President Joe Biden in 2020. Democrats hope that the issue of abortion rights will help turn out more voters and potentially flip the statehouse blue, while Republicans grapple with the political fallout of the extreme 1864 ban and the competing priorities of their conservative base and more moderate swing voters.

As the Senate prepares to vote on the repeal, Arizona Attorney General Kris Mayes, a Democrat, has vowed not to enforce the 1864 ban in the meantime. Providers, including Planned Parenthood, are also preparing resources to help patients seeking abortions travel out of state during the period when the ban may be in effect.