On the steps of the Irish Embassy in London on Saturday, hundreds gathered to hear the words of Irish activists, alongside chants“Get your rosaries of my ovaries!”—poetry, and speeches. It was a rally in opposition to Ireland’s abortion bans, which are among the strictest in Europe. Women face up to 14 years in jail for terminating a pregnancy in the Republic of Ireland; across the border in Northern Ireland, the sentence can be life in prison. The protest was one of more than 20 that day in cities around the world, held in solidarity with the sixth annual March for Choice held in Dublin, which attracted thousands. The crowd was young, with most attendees ranging in age from early 20s to mid-30s, and optimistic in mood; last week, on September 26, it was announced that Ireland will hold a referendum on the question, with voters deciding whether or not to legalize abortion this coming May.

The rallies were organized by a grassroots abortion rights organizations, with aims to repeal the Eighth Amendment of the Irish Constitution. They’ve been boosted along by national efforts to reform Ireland’s constitution, with direct input from citizens. Passed with a popular vote of nearly 67 percent in 1983, the Eighth Amendment outlines that the Irish State “acknowledges the right to life of the unborn.” The amendment is a ban on abortion, and though there are some exceptions and selective enforcement, it amounts to a complete ban. Exceptions aren’t always made to save the life of the mother: Anti-amendment activists say that the Eighth Amendment places higher importance on the life of an fetus than on that of the woman carrying it.

There’s some evidence that the law does just that. A watershed moment for pro-choice movement in Ireland was the death of Savita Halappanavar, a 31-year-old dentist from India who died in October 2012, at University Hospital Galway, due to complications of a septic miscarriage at 17 weeks. Ms. Halappanavar and her husband had requested an abortion upon learning that miscarriage was inevitable, but they were told that this was not possible, due to Ireland being “a Catholic country.” Medically, her death was entirely avoidable; politically, it became a lightening rod for issues of misogyny, bodily autonomy, and personal rights in the country. Halappanavar’s death brought global attention to Ireland’s extreme abortion laws and played a key part in mobilizing pro-choice sentiment there. For the first time in decades, a re-examining of the Eighth Amendment became politically feasible.

This moment has been a long time coming. Mrs. Halappanavar’s death was the first in a string of high profile forced pregnancy cases that enraged the public. In 2014, Ms. Y, an asylum seeker, arrived in the Republic of Ireland from abroad. Stating she was pregnant due to having been raped in her home country, she sought an abortion, asserting suicidal feelings. The Irish people voted to make suicide risk a viable cause for a legal abortion in 1992, but Ms. Y’s request was denied. She travelled to the UK to procure an abortion, but was arrested for illegally entering the country.

 Though Ms. Y was declared suicidal by two psychiatrists and went on hunger strike, the Health Service Executive in Ireland obtained a court order to forcibly hydrate her, and a baby was delivered by involuntary caesarean section at 25 weeks. She has sued the Irish state for assault. As recently as 2016, a suicidal pregnant minor was placed against her will in a mental health institution in Dublin, instead of being permitted the abortion she sought. She, too, was forced to deliver a child.

Mrs. Halappanavar’s death was the first in a string of high profile forced pregnancy cases that enraged the public.

These cases and others galvanized an enormous popular movement for women’s rights in Ireland, with a calls for a referendum ultimately being embraced by every one of the nation’s liberal parties. The political pressure became enormous, and finally the referendum was announced by Prime Minister Leo Varadkar in the Irish Assembly last week.

Mr. Varadkar is a former medical doctor, and his father, like Ms. Halappanavar, is an Indian immigrant. At 38 he is Ireland’s youngest prime minister, and also its first openly gay head of government. Mr. Varadkar has been heralded by many as a symbol of how rapidly Irish society has evolved, from a vehemently traditional and racially homogenous Catholic country to a much more liberal and multicultural one. After all, divorce was not legal in Ireland until 1996, and gay sex was illegal until 1993. But by 2015, things had changed enough that the Republic of Ireland became the first nation in Europe to legalize same-sex marriage by popular vote.

Some of his critics feel that Mr Varadkar’s progressivism is overstated; his party, Fine Gael, is center-right, favoring free market policies and erring toward conservatism on social issues. While he promises a referendum, he has in the past dismissed the view that abortion access is a class issue—even in a country where getting an abortion means an expensive trip abroad—and expressed frustration at being challenged on the issue of women’s rights. As recently as mid-September, he stated that he does not believe Ireland is “ready” for abortion on demand.

But he may not have a choice. The announcement of the referendum follows several months of deliberation among the new Citizen’s Assembly. Established in 2016, it is a body that is aimed at directly involving Irish citizens in political change. The Citizen’s Assembly was a successor to the 2012 to 2014 Constitutional Convention, which was established after the 2011 Parliament elections. The Fine Gael and Labour partie that formed the government had included proposals to reform the Irish constitution in their election manifestos—once they got into office, the Assembly was one of their attempts to make good on those promises. After hearing from a group of experts and advocates on both sides of the debate, a majority of those convened in the Assembly wanted to revise the national ban on abortion.

 This was not what anyone was expecting—not even Repeal the Eighth activists. While the Citizen’s Assembly was posited as an innovative approach to liberal constitutional reform, the Abortion Rights Campaign have been fiercely critical. “We always stated that we believed the Citizens’ Assembly to be a stalling tactic by the Government,” Claire Lanigan, a spokeswoman for the group, told me. Maybe it was, but the results have been decidedly in their favor. She said, “When Irish people are given the facts about abortion, and the real effects of denying access at home, they will come to a pro-choice position.”