US faces seismic abortion shift, Biden backs 'fundamental' right

President Joe Biden called on American voters Tuesday to defend the "fundamental" right to abortion after a leaked draft suggested the Supreme Court is poised to strike down the longstanding decision protecting a woman's right to terminate a pregnancy.

The opinion by the court's conservative majority hit Washington like a thunderclap late Monday, setting up a potentially historic turning point on a hot-button issue that is now certain to dominate November's midterm elections.

If the draft is made official -- which could happen within months -- it would shred half a century of constitutional protections for abortion rights, and give free rein to Republican-controlled states which are already leading an all-out push to curtail the procedure.

Biden's Democrats stand broadly united in support of abortion rights -- and rallied immediately in defence of the watershed 1973 Roe v. Wade decision.

While he cautioned the draft had not been verified, Biden said US voters will have to step up in defense of the right if the Supreme Court moves ahead.

"I believe that a woman's right to choose is fundamental, Roe has been the law of the land for almost fifty years, and basic fairness and the...