“Abortion presents a profound moral question,” read the court ruling. “The Constitution does not prohibit the citizens of each State from regulating or prohibiting abortion. Roe and Casey (a 1992 decision that reaffirmed federal abortion rights) arrogated that authority. We now overrule those decisions and return that authority to the people and their elected representatives.”

Within an hour of the ruling on Friday (Saturday AEST),the street outside the court was filled with demonstrators either protesting or celebrating the decision.

While pro-life activists were thrilled - many screaming and dancing with joy - critics say the ruling represents one of the most damaging setbacks to the rights of women in America’s history.

President Joe Biden said it was “a sad day for the court and for the country” and described the court’s action as “the realisation of extreme ideology”.

“Now with Roe gone,let’s be very clear:the health and life of women of this nation are now at risk,” he said.

Pro-choice groups agreed,warning the court’s decision could lead to more unsafe procedures,result in unwanted pregnancies,or place pressure on the states that continue to offer services as more people turn to them for treatment.

“Utter chaos lies ahead,as some states race to the bottom with criminal abortion bans,forcing people to travel across multiple state lines and,for those without means to travel,carry their pregnancies to term - dictating their health,lives,and futures,” said Nancy Northup,president of the Centre for Reproductive Rights.

Another restrictive state is Oklahoma, where the Republican government recently introduced new laws prohibiting nearly all abortions starting at fertilisation,accompanied by a bounty-hunting scheme encouraging members of the public to sue those involved in abortions and rewarding them with at least $US10,000 ($14,400) if their lawsuit is successful.

In his ruling,Alito reiterated his view that the law was “egregiously wrong” and “on a collision course with the constitution from the day it was decided”.

The court’s three Democratic appointees – Justices Stephen Breyer,Sonia Sotomayor and Elena Kagan - filed a joint dissent,writing that “whatever the exact scope of the coming laws,one result of today’s decision is certain:the curtailment of women’s rights,and of their status as free and equal citizens”.

Chief Justice John Roberts took a more nuanced view,voting with the conservative majority but stopping short of overrulingRoe v Wade outright.

The decision has set the scene for an explosive showdown between pro-choice and pro-life activists in the lead up to November’s midterm elections,and has paved the way for even deeper divisions across the country.

Trump praised the court’s decision,telling Fox News:“This is following the constitution,and giving rights back when they should have been given long ago. I think,in the end,this is something that will work out for everybody.”

His former vice president,Mike Pence,who is also seen as a contender for the 2024 presidential nomination,went one step further,calling for a national ban.

Republican Senate Minority Leader Mitch McConnell described the ruling as “courageous and correct”,while Democrat House Speaker Nancy Pelosi said it was “a slap in the face to women”.

Former president Barack Obama also weighed in,issuing a statement saying:“Today,the Supreme Court not only reversed nearly 50 years of precedent,it relegated the most intensely personal decision someone can make to the whims of politicians and ideologues - attacking the essential freedoms of millions of Americans.”

Michelle Obama released a long statement on social media,saying her heart ached.

“I am heartbroken for people around this country who just lost the fundamental right to make informed decisions about their own bodies[...] That is what our mothers and grandmothers and great-grandmothers lived through and now here we are again,” the former first lady wrote.

She was joined by New Zealand Prime Minister Jacinda Ardern who described the ruling as “incredibly upsetting”. Ardern said seeing American women lose the right to choose felt “like a loss for women everywhere”.

Tensions were already high in the lead up to the ruling,with steel fencing installed around the Supreme Court last month ahead of potential unrest and security beefed up to protect the nine justices of the court.

Last month,a man was also arrested near the Maryland home of Justice Brett Kavanaugh over an alleged attempt to assassinate him.

One man,John,who did not wish to give his surname,was standing in the crowd outside the Supreme Court holding a sign that said:“Save our Democracy. Pack the court. Do it Now.”

“I’m here because I’m angry,all the women I know are angry,and my fiance is absolutely infuriated,” he toldThe Age/Sydney Morning Herald. “I strongly favour packing the court - expanding the size of the court to ensure that it reflects the thinking of the majority of Americans.”

A few meters down the street,Shannon Russell was standing with a group of friends from the organisation Catholics for Choice,holding a sign that said:“Thou Shalt Not Steal My Civil Rights”.

“It often surprises people when I tell them that 68 per cent of Catholics support Roe v Wade and one in four abortion patients identify as Catholics,” Russell said.

“So we need to start listening to people who have abortions and who need abortion care,and to stop stigmatising them. And we can no longer trust these justices over there to uphold even our most basic fundamental rights,so we have to take our fight to Congress and the President.”

The decision was based on a Mississippi case known asDobbs v Jackson Women’s Health Organisation,which relates to a law that banned abortions after 15 weeks of pregnancy. This law overturned the protections afforded byRoe v Wade,which determined that every person has the right to end a pregnancy before viability,which is typically around 24 weeks. An abortion clinic in Mississippi sued,and that led to the case eventually making its way to the Supreme Court last December.

Get a note directly from our foreigncorrespondentson what’s making headlines around the world.Sign up for the weekly What in the World newsletter here.