The Supreme Court has ended constitutional protections for abortion that have been in place for nearly 50 years in a decision by its conservative majority to overturn Roe v Wade.
The ruling is expected to lead to abortion bans in roughly half of US states.
The decision was the culmination of decades of efforts by abortion opponents, made possible by an emboldened right side of the court that has been fortified by three appointees of former president Donald Trump.
The ruling came more than a month after the stunning leak of a draft opinion by Justice Samuel Alito indicating the court was prepared to take this momentous step.
But what exactly is Roe v. Wade, and how has it affected abortion legislation over the last half a century?
Here is everything you need to know about it.
What is Roe v. Wade?
Roe v. Wade is a historic 1973 Supreme Court decision in which the Court ruled that a pregnant woman's right to choose whether or not to have an abortion is protected by the Constitution of the United States.
Simply put, many federal and state abortion laws banning the practice in the United States were reversed as a result of the judgement, making abortion legal in many circumstances.
Roe sparked a national debate in the United States regarding whether or to what extent abortion should be allowed, who should decide on its legality, and what role moral and religious beliefs should have in politics.
Who are ‘Roe’ and ‘Wade’?
The case involved Norma McCorvey - who used the legal alias "Jane Roe" - who fell pregnant with her third child in 1969.
McCorvey wanted an abortion but resided in Texas, where it was illegal to do so unless it was absolutely essential to save the mother's life.
Her attorneys filed a case in federal court on her behalf against Henry Wade, her local district attorney, saying that Texas' abortion restrictions were illegal.
The case was considered by a three-judge panel of the United States District Court for the Northern District of Texas, which found in her favour.
The state of Texas then took its case to the Supreme Court.
The Court ruled in McCorvey's favour, finding that a clause of the 14th Amendment of the United States Constitution protects a pregnant woman's freedom to choose whether or not to have an abortion.
Did it make abortion legal?
Roe v. Wade removed many legal restrictions on a person’s right to choose whether to have an abortion, but it didn’t completely legalise the practice.
The Court’s ruling stated that the right to an abortion is not absolute and must be weighed against the governments interests in preserving foetal life and the health of women - the ruling affected the laws of 46 US states.
The Court connected state control of abortion to the three trimesters of pregnancy.
Governments could not prohibit abortions during the first trimester; any law prohibiting abortions during the first trimester would be deemed unconstitutional.
During the second trimester, governments could impose “reasonable” health regulations only to protect the health of the mother.
And during the third trimester, abortions could be outright prohibited, with exceptions for cases where they were necessary to save the mother's life or health.
In a similar ruling in 1992, the Supreme Court again said a woman's right to choose whether or not to have an abortion is constitutionally protected, but abandoned Roe's trimester framework.
Instead, “foetal viablitiy” was to be considered: the Supreme Court ruled that states could not impose an "undue burden" on women seeking abortions before a foetus could survive outside the womb - around 24 weeks.
Why was Roe v. Wade be overturned?
The decision on Roe v Wade came at a time when reproductive rights are under attack in Republican-leaning states across the United States; several Republican-led states had already passed highly restrictive abortion laws.
Justice Alito, in the final opinion issued on Friday, wrote that Roe and Planned Parenthood v Casey, the 1992 decision that reaffirmed the right to abortion, was wrong the day it was decided and must be overturned.
Authority to regulate abortion rests with the political branches, not the courts, Justice Alito wrote.
Joining him were Justices Clarence Thomas, Neil Gorsuch, Brett Kavanaugh and Amy Coney Barrett. The latter three justices are Trump appointees. Justice Thomas first voted to overrule Roe 30 years ago.
Chief Justice John Roberts would have stopped short of ending the abortion right, noting that he would have upheld the Mississippi law at the heart of the case, a ban on abortion after 15 weeks, and said no more.
Justices Stephen Breyer, Sonia Sotomayor and Elena Kagan — the diminished liberal wing of the court — were in dissent.
The ruling is expected to disproportionately affect minority women who already face limited access to healthcare, according to statistics analysed by The Associated Press.
Thirteen states, mainly in the South and Midwest, already have laws on the books that ban abortion in the event Roe is overturned. Another half-dozen states have near-total bans or prohibitions after six weeks of pregnancy, before many women know they are pregnant.
In roughly a half-dozen other states, the fight will be over dormant abortion bans that were enacted before Roe was decided in 1973 or new proposals to sharply limit when abortions can be performed, according to the Guttmacher Institute, a research group that supports abortion rights.
In Wisconsin, which has an 1849 abortion ban on the books, Planned Parenthood immediately halted all scheduled abortions at its clinics in Madison and Milwaukee following the court’s ruling.
More than 90% of abortions take place in the first 13 weeks of pregnancy, and more than half are now done with pills, not surgery, according to data compiled by Guttmacher.
What has the reaction been?
President Joe Biden is to speak from the White House about the US Supreme Court ruling overturning Roe v Wade – the landmark decision that legalised abortion nationwide.
The remarks will outline his approach to the new phase in the fight over abortion access.
The White House has been preparing for this moment since a draft of the decision leaked in May.
Officials have been huddling with state leaders, advocates, healthcare professionals and others to prepare for a future without Roe v Wade.
Outside the Supreme Court, a crowd of abortion supporters swelled to the hundreds after the ruling was issued. One chanted into a megaphone: “legal abortion on demand” and “this decision must not stand”.