The surprise vote in Republican-heavy Kansas to repudiate a push for abortion bans fired shockwaves through the US political landscape ahead of November's midterm elections, with President Joe Biden's Democrats now seeing a glimmer of hope that they may avoid their predicted drubbing.

Ever since the Supreme Court overturned the nationwide right to terminate a pregnancy in June, US conservatives have been nervously asking whether their triumphant push to severely restrict access to the procedure -- a decades-long dream -- has gone too far in the run-up to the midterms.

In Kansas, they got an answer.

The state is a Republican stronghold, but in Tuesday's referendum, a bid to remove abortion rights from the Kansas constitution was rejected by 59 to 41 percent, with unusually heavy turnout.

Given this was the first time Americans had an opportunity to vote on the issue since the conservative-dominated Supreme Court ruled to overturn the half-century-old Roe v. Wade decision enshrining abortion rights, Democrats are rejoicing -- and say the backlash is only beginning.

"Tonight's overwhelming defeat of the ballot referendum in Kansas shows the massive support for abortion rights among voters, and serves as a clear warning to anti-abortion politicians across the country: their time is up," said Planned Parenthood, which lobbies for abortion access.

"As the first state to vote on abortion rights following the fall of Roe v. Wade, Kansas is a model for a path to restoring reproductive rights across the country through direct democracy," said the group's president Alexis McGill Johnson, who also leads the Planned Parenthood Action Fund.

"We have the opportunity to protect abortion access at the ballot box in November. We know that Kansas will not be our last fight or our last victory."

Or, as former Democratic senator Claire McCaskill told MSNBC after the vote: "This should be a big flashing signal to every Democratic candidate out there."

Trump card

The November midterms, which will decide which party controls Congress for the last two years of Biden's first term, is shaping up as rough for Democrats who even now only control the legislature by a few votes.

Blamed by voters for soaring inflation -- at a four-decade high -- and widespread pessimism in the messy aftermath of the Covid-19 pandemic, Democrats are forecast to lose at least the House of Representatives and maybe the Senate.

This would likely make Biden a lame duck, turning Washington into an even uglier political battlefield than it is today.

And abortion is not the only reason the midterms campaign will bring ideological tensions to a boil.

Donald Trump is pushing hardline right-wing candidates to boost his brand and possibly set the stage for his own attempted White House comeback in 2024.

Several candidates endorsed by Trump won primary votes held around the United States on Tuesday at the same time as the Kansas referendum, signaling that the disgraced ex-president remains a force.

In Michigan, one of the handful of House Republicans who dared join Democrats in impeaching Trump as president was tossed out, replaced by a former Trump administration official.

Trump's candidate for the Senate, Blake Masters, won the Republican primary in the swing state of Arizona.

And Trump's candidate for the sensitive post of Arizona secretary of state, a key figure in running elections, also won. Mark Finchem, a supporter of Trump's lie that the 2020 presidential election was stolen, has ties to a far-right militia.

Increasingly, Democrats are seeking to link that Trump surge and the abortion dispute, arguing that the midterms will be a battle not just between two parties but generally between political moderates and growing extremism.

Across the country, Democrats have even gone so far as to pay for advertising boosting Trump's primary candidates -- the theory being that they will be easier to beat in November than more moderate Republicans.

For example, according to The New York Times, the Democratic side spent about $627,000 on advertising in Maryland to help Trump-endorsed candidate Dan Cox -- another 2020 election lie supporter -- win his Republican gubernatorial primary.