Kansas voters have rejected a move to restrict or outright ban abortion access in the conservative state, voting against a change to their constitution this week.
The proposed amendment to the Kansas constitution would have added language stating it did not grant the right to abortion.
A 2019 state Supreme Court decision declared access to abortion a "fundamental" right under the state's bill of rights, preventing a ban and potentially thwarting legislative efforts to enact new restrictions.
Tuesday's result was unexpected in the Republican-controlled state and the first major test of voter sentiment since the US Supreme Court ruled to overturn Roe v Wade, a 1973 decision which legalised abortion.
The referendum was closely watched as a measure of liberal and moderate voters' anger over the Supreme Court's ruling.
The result also has potential implications for the upcoming midterm election in November.
While it was just one state, the heavy turnout for an August primary that typically favours Republicans was a major victory for abortion rights advocates.
With most of the vote counted, they were prevailing by roughly 20 percentage points, with the turnout approaching what is typical for an autumn election for governor.
The Kansas vote also came as a warning to Republicans who had celebrated the Supreme Court ruling and were moving swiftly with abortion bans or near-bans in nearly half the states.
"Kansans bluntly rejected anti-abortion politicians' attempts at creating a reproductive police state," said Unite for Reproductive & Gender Equity's executive director Kimberly Inez McGuire.
"Today's vote was a powerful rebuke and a promise of the mounting resistance."
It also provided a dash of hope for Democrats nationwide grasping for a game changer during an election year otherwise filled with dark omens for their prospects in November.
"This vote makes clear what we know: The majority of Americans agree that women should have access to abortion and should have the right to make their own health care decisions," US President Joe Biden said in a statement.
After calling on Congress to "restore the protections of Roe" in federal law, Mr Biden added: "And the American people must continue to use their voices to protect the right to women's health care, including abortion."
Twice as many Republicans as Democrats have voted in the state's August primaries in the decade leading up to Tuesday's election.
Anti-abortion politicians wanted to have the vote coincide with the state's August primary, arguing they wanted to make sure it got the focus, though others saw it as an obvious attempt to boost their chances of winning.
Opponents of the measure predicted that the anti-abortion groups and politicians behind the measure would push quickly for an abortion ban if voters approved it.
Before the vote, the measure's supporters refused to say whether they would pursue a ban as they appealed to voters who supported both some restrictions and some access to abortion.
An anonymous group sent a misleading text on Monday to Kansas voters telling them to "vote yes" to protect choice, but it was suspended late on Monday from the Twilio messaging platform it was using, a spokesperson said.
Twilio did not identify the sender.
The Kansas vote is the start of what could be a long-running series of legal battles playing out where officials are more conservative on abortion than governors or state courts.
Kentucky will vote in November on whether to add language similar to Kansas' proposed amendment to its state constitution.
Meanwhile, Vermont will decide in November whether to add an abortion rights provision to its constitution. A similar question is likely headed to the November ballot in Michigan.
In Kansas, both sides together spent more than $US14 million ($20.1m) on their campaigns.
'I want her to have the same rights my mother has had'
Spokesperson for the pro-amendment campaign Emily Massey said the outcome was a "temporary setback".
"Our dedicated fight to value women and babies is far from over," she said.
The electorate in Tuesday's vote was not typical for a Kansas primary, particularly because tens of thousands of unaffiliated voters cast ballots.
Kristy Winter, 52, a Kansas City-area teacher and unaffiliated voter, voted against the measure and brought her 16-year-old daughter with her to her polling place.
"I want her to have the same right to do what she feels is necessary, mostly in the case of rape or incest," she said.
"I want her to have the same rights my mother has had most of her life."
Mallory Carroll, the spokesperson for the national anti-abortion group Susan B. Anthony Pro-Life America, described the vote as "a huge disappointment" for the movement.
She called on anti-abortion candidates to "go on the offensive".
"We must work exponentially harder to achieve and maintain protections for unborn children and their mothers," she said.
Stephanie Kostreva, a 40-year-old school nurse from the Kansas City area and a Democrat, said she voted in favour of the measure because she was a Christian and believed life began at conception.
"I'm not full scale that there should never be an abortion," she said.
"I know there are medical emergencies, and when the mother's life is in danger there is no reason for two people to die."
Kansas' anti-abortion history
The measure's failure was also significant because of Kansas' connections to anti-abortion activists.
Anti-abortion Summer of Mercy protests in 1991 inspired abortion opponents to take over the Kansas Republican Party and make the legislature more conservative.
Thousands of anti-abortion protesters flocked to three clinics in the state's largest city of Wichita, with over 2,600 arrests over six weeks at sit-in protests and blockades.
They were there because a Wichita clinic run by doctor George Tiller was among the few in the US known to do abortions late in pregnancy.
The harassment culminated in a rally which filled Wichita's 24,000-seat Cessna Stadium.
Dr Tiller was murdered in 2009 by an anti-abortion extremist.
The state has had strong anti-abortion majorities in its legislature for 30 years, but voters have regularly elected Democratic governors, including Laura Kelly in 2018.
She opposed the proposed amendment, saying changing the state constitution would "throw the state back into the Dark Ages".
ABC/AP
