Alabama’s new law restricting abortion in nearly every circumstance has moved one of the most polarising issues in American politics to the centre of the 2020 presidential campaign.

The state’s legislation — the toughest of several anti-abortion measures that have passed recently – — prompted an outcry from Democratic presidential candidates, who warned that conservatives were laying the groundwork to undermine the landmark Roe v Wade decision.

The White House did not comment on the Alabama bill, signed into law by Republican Governor Kay Ivey, as President Donald Trump tries to balance his conservative base against the potential of antagonising women who are already sceptical about his presidency.

The furore over abortion quickly took over on the Democratic campaign trail.

Rallying supporters in New Hampshire, Senator Kamala Harris said she would back a legal challenge to Alabama and Georgia’s restrictive abortion laws.

She also vowed to make a commitment to upholding the Roe decision a “significant factor” in any Supreme Court nominees she might choose as president.

However, she declined to go as far as presidential rival Senator Kirsten Gillibrand, who has promised to only nominate judges ready to preserve the 1973 ruling that established a woman’s constitutional right to an abortion.

“I respect every woman’s right to make a decision about what’s in the best interest of herself and her family,” Ms Harris said.

Kentucky, Mississippi, Ohio and Georgia have approved abortion bans once a foetal heartbeat is detected, which can occur in about the sixth week of pregnancy.

None of these laws are yet in force, either because of later effective dates or legal challenges that have blocked them. But supporters have openly predicted that the laws could spark court fights that will eventually lead the Supreme Court to revisit its Roe decision.

Ms Gillibrand plans to fly to Atlanta on Thursday to meet with women protesting against Georgia’s state law.

Democratic presidential candidate Senator Kirsten Gillibrand has vowed to fight the anti-abortion moves Credit: Charles Krupa/AP

Senator Cory Booker said that backers of the Alabama measure are “saying that they designed this bill with certain provisions — like not having any exceptions for rape or incest — specifically designed so that they can lead a fight to the Supreme Court” to “undermine other freedoms and liberties of women to control their own bodies”.

Mr Booker said it is not enough to hope that Roe will be upheld, adding: “We cannot wait to see if this gets worse.”

Several Democratic presidential candidates sought to use their high-profile positions to boost organising against the state-level abortion laws.

Ms Harris emailed her campaign supporters offering to “split a donation” to four advocacy groups working to defend abortion rights. Pete Buttigieg, mayor of South Bend, Indiana, directed his supporters by email to the abortion-rights group NARAL.

Among the other Democratic candidates who took to Twitter to blast Alabama’s law and other state-level restrictions were Senators Elizabeth Warren of Massachusetts, Bernie Sanders of Vermont and Amy Klobuchar of Minnesota, as well as former Vice President Joe Biden and former Texas Representative Beto O’Rourke.

Ilyse Hogue, the president of NARAL, lauded the Democrats for their support. But she urged them to go further than pro-abortion rights rhetoric, calling instead for “articulated plans about how we’re going to address and get out of this crisis”.

The Democratic pushback comes as Mr Trump makes his selection of conservative judges a centrepiece of his political stump speech, part of a long-running courtship of social conservatives whose support he needs to win reelection next year.

Republicans have long believed that the politics of abortion have shifted somewhat in their favour in recent years. But the near-absolutist nature of the most recent bills has sparked some concern among the president’s team that it could energise Trump critics and female voters, with whom the president has long struggled.