Exit polls indicated Irish voters were expected to repeal the Republic of Ireland's constitutional prohibition against blasphemy, with close to 70 percent of voters backing the change in a Friday vote, the Irish Times has reported.
Catholic bishops did not put forward a defense of the law, though one Muslim leader spoke in its favor.
"The publication or utterance of blasphemous, seditious, or indecent matter is an offence which shall be punishable in accordance with law," said the constitutional passage in question, which dates back to 1937.
As passed, the referendum would remove blasphemy from this list of offenses, and allow the Irish parliament to change laws penalizing blaspemy.
The referendum did not receive much criticism from Catholic leaders.
In comments at the conclusion of their autumn meeting, the Irish Catholic Bishops' Conference said the reference to blasphemy in the constitution is "largely obsolete and may give rise to concern because of the way such measures have been used to justify violence and oppression against minorities in other parts of the world."
"The human right of faith communities to contribute to public life, including public debate on issues that are of importance to everyone, without being subjected to attack or ridicule, needs to be acknowledged and respected," they added.
The bishops said that the social fabric is enriched by promoting the freedom of religion and freedom of conscience for everyone. They also voiced solidarity with Christians and others throughout the world suffering persecution and human rights abuses because of their faith or beliefs.
The implementing law against blasphemy, the Defamation Act of 2009, makes blasphemy a crime punishable by up to a 25,000 Euro fine, about $28,000. It defines blasphemy as "something that is grossly abusive or insulting in relation to matters held sacred by any religion, thereby causing outrage among a substantial number of the adherents of that religion."
No one has been prosecuted under the 2009 legislation.
Irish Minister for Justice Charlie Flanagan, who advanced the referendum proposal, said its passage would "confirm our status as a modern, democratic society."
"I believe it's timely that we affirm our belief in a more inclusive society where communication between those of different belief systems can take place on an equal basis with tolerance and respect as guiding principles," he said in September, according to the Irish Examiner.
While removing the offense from the constitution seems like a small thing, Flanagan said, "nonetheless, I believe it's deeply symbolic in a very tangible way and it would confirm our status as a modern, democratic society."
The last blasphemy prosecution took place in 1855, long predating the Republic of Ireland's constitution. A Redemptorist priest was collecting evil literature to burn, and unknowingly burned a copy of the Bible, BBC reports. The court found him not guilty on the grounds he did not intend to burn the Bible.  
In 2015 police investigated the comedian Stephen Fry after he described God as "utterly evil, capricious and monstrous," among other denigrating comments, for a show on the state broadcaster RTE.
Police dropped the investigation after deciding an insufficient number of people were outraged.
An Irish Times poll held ahead of the vote found support to strike the blasphemy law highest in Dublin, at 63 percent, and weakest in Connaught-Ulster, where 45 percent said they were in favor and 31 percent against.
Older voters were least likely to support changing the constitution, while wealthier voters were more likely to support a change.
Dr. Ali Selim from the Islamic Cultural Centre in Dublin was among the defenders of the law, telling CatholicIreland.net in June that the law functions "to organize our relationship when it comes to sensitive matters."
"Religion for me is something very important but for somebody who is not a believer, religion is nothing," he said. "That's fine. You can believe the way you want to believe because the law of this country gives you this right. But because it is important for me and not important for you then when it comes to the way religious affairs are addressed, then we need regulations that you and I should abide by."
He said that while it's acceptable for someone to present their non-belief in Catholicism, for instance, if he is presenting Catholicism in a mocking way "that should not be accepted because it is something important for others."
"It all comes under the concept of reciprocal respect," he said.
The Irish constitution's preamble still begins "in the Name of the Most Holy Trinity" and acknowledges "all our obligations to our Divine Lord, Jesus Christ, Who sustained our fathers through centuries of trial." Its text continues to read "the State acknowledges that the homage of public worship is due to Almighty God. It shall hold His Name in reverence, and shall respect and honor religion."
While 20th century Ireland was a strongly Catholic society where lay political leaders implemented Catholic faith and morals as they perceived them, sometimes in close cooperation with Church leaders and other Catholic institutions, in recent decades the country has secularized.
While Ireland has higher Mass attendance rates than many traditionally Catholic countries in Europe, vocation numbers have plummeted and self-identified Catholics have dropped to 78 percent, according to the 2016 census, and almost one in ten now identify as having no religion.
The secularizing changes are attributed to scandals involving clergy sex abuse, other abuse in other Catholic-run institutions, as well as increasing affluence and influence from international corporations and NGOs.
Ireland's long-standing pro-life constitutional protections were repealed in a May 2018 vote with over 66 percent voting in favor. In May 2015 Ireland became the first country to implement gay marriage by a popular vote, with 62 percent of voters backing the change.
Ireland is one of 71 countries where blasphemy is illegal.
In countries like Iran and Pakistan, blasphemy is sometimes punished by the death penalty.
Critics of Pakistan's strict blasphemy law have been assassinated, such as Punjab Gov. Salman Taseer, who was killed in 2011. Accusations of blasphemy sometimes target non-Muslim minorities. Pakistani Christian Asia Bibi was convicted of blasphemy in 2010, a charge she denies. Her case is pending appeal.
Ireland's Friday vote coincided with the election of the Republic of Ireland's president, a largely ceremonial role. Incumbent Michael D. Higgins, 77, appeared headed for re-election with about 55 percent of the vote, though rival candidate Peter Casey, a business entrepreneur, put in an unexpectedly strong showing with about 20 percent of the vote.