As Ireland votes in a historic referendum on abortion on Friday, there are concerns that campaigners have been resorting to some of the same tactics used in the U.S. presidential election and Brexit referendum to sway undecided voters.

Social media have been awash with bots retweeting opinions and articles with a strong anti-abortion-rights message, according to observers, while Facebook users have been bombarded with privately sponsored or anonymous ads that are popping up in their feeds in an attempt to influence their decisions, according to data from the nonprofit Transparent Referendum Initiative.

Earlier, Google Inc. GOOG, -3.36% said it will block all ads about the referendum from its search engine and YouTube.

“There is no doubt there’s an incredibly well-funded opposition campaign,” said Tara Flynn, an Irish comedian, actress and activist for abortion rights. “They were ready to go from the start, and they raised a quarter of a million [euros] in one day. There’s a great deal of misinformation in the public domain.”

David Quinn, founder of the socially conservative Catholic group the Iona Institute, dismissed those concerns: “Of course mainstream media dislike social-media advertising by pro-lifers,” he wrote in a tweet. ”Such ads are a way of doing an end-run around media bias.”

Matthew Mulligan, a journalist at the social-media intelligence and news agency Storyful, which sources and verifies online content, said his company has found many videos and digital ads from anonymous sources that are fake. (Storyful is owned by News Corp, the owner of MarketWatch parent Dow Jones.)

In one example, a video purporting to represent the official “no” campaign, featured a man posing as a hospital porter who claimed he had worked in England in “abortion wards.” Another video was uploaded by hackers to a fake YouTube account called RTÉ News, after Ireland’s national broadcaster RTÉ, and included people posing as doctors, discussing their regrets about their past involvement with abortion.

“There are Facebook FB, -2.05% accounts like Undecided on the 8th or Facts About the 8th, that are supposed to be neutral, but often they are not linked, there’s no website address, so it’s a bit of a Wild West,” said Mulligan. “The problem is there’s no regulation. Anyone can make an ad. There’s no official registration required.”

Storyful is monitoring about 200 Facebook pages on a daily basis, some of which feature posts from smaller fringe groups, said Mulligan. “Our sense is that the ‘no’ campaign is far outspending the repeal campaign, but there is very little transparency.”

Facebook also blocked all ads on the referendum that come from advertisers outside of Ireland and has pledged to implement the same rule for any future elections in Ireland. That’s good news for a series of coming referendums on constitutional reform, but it’s too late to block the 8th Amendment referendum from undue influence, said Gavin Sheridan, founder of legal startup Vizlegal.

“There is very little visibility on how many ads are being run, no idea on who is behind them, no idea about the amounts of money being spent,” he said. “It’s just opaque.”

What’s more, Facebook’s move did not prevent organizations and individuals from simply donating to groups that are located in Ireland. Media reports suggest conservative and pro-life groups from the U.S. are a major source of funding for the “no” campaign.

What Irish citizens are being asked to vote on

The referendum is not a straightforward yes or no vote on abortion, but rather a choice between repealing or upholding an amendment to the constitution introduced in 1983 that gives equal rights to a pregnant woman and an unborn fetus. If the amendment is repealed, it is expected to lead the Irish government to allow abortion for a restricted period of up to 12 weeks after conception.

The reason for the referendum: The wording of the amendment (see below) has had consequences for some women whose pregnancies have gone wrong, as they wereunable to terminate nonviable pregnancies. It has ensured that Ireland has some of the most restrictive laws on abortion in the world, with no exceptions, even in the case of rape or incest.

“ ‘The State acknowledges the right to life of the unborn and, with due regard to the equal right to life of the mother, guarantees in its laws to respect, and, as far as practicable, by its laws to defend and vindicate that right.’ ” — Eighth Amendment of the Irish constitution

The amendment is widely viewed as contributing to at least one high-profile death: that of Indian dentist Savita Halappanavar, who was refused an abortion in a Galway hospital in 2012 during a miscarriage that lasted three days. Halappanavar died of sepsis. An inquest found her death was caused by “medical misadventure” as doctors failed to intervene until it was too late.

The 1983 referendum happened at a time when the Catholic Church had a strong role in Irish society, but that has greatly changed. The sexual-abuse scandals involving members of the clergy that broke in the 1990s and 2000s have dramatically weakened the influence of the church in Ireland, which once virtually co-governed and ran many schools and institutions.

The success of the marriage-equality referendum in 2015 has raised hope that Ireland has changed sufficiently since the 1980s that it is now ready to fully embrace women’s reproductive rights.

”There is a motivated campaign for yes,” said Flynn. “There are so many women who have kept secrets for a long time, [and] now they are telling what are really heartbreaking stories.”

Quinn of the Iona Institute is unmoved. If the amendment is repealed, “We will have explicitly declared that the unborn have no right to life under our constitution,” he said.

Why hold a referendum?

The referendum is necessary because the Irish constitution includes a provision stipulating that any change must be voted on by the whole nation — one reason that Ireland has in the past voted on issues including divorce and marriage equality.

In 1992, after a scandal involving a 14-year-old rape victim who was refused the right to travel abroad for an abortion, the constitution was again amended to add language to allow access to information about abortion and to grant the right to travel to receive abortion care overseas.

But as Together for Yes, an umbrella group for a range of constituencies that support repeal, notes, not every woman can afford the cost of travel, and overseas procedures include no follow-up care back home. The penalty for an illegal abortion in Ireland, either by back-street means or through the use of abortion pills, is a 14-year prison term.

Together for Yes says it has been fully transparent about its fundraising, which takes in money from personal donations, big and small, as well as corporate donations, all from within Ireland. The group provides and maintains a donor charter on its website.

That transparency is not being matched by the “no” groups. The Iona Institute has a prominent page seeking donations, but no further information. The Iona Institute, Let Them Live and the Catholic G.K. Chesterton Society, did not return requests for comment.

At least two Irish women travel to England every week after receiving diagnoses of fatal fetal anomalies, as it is the only way to have a nonviable pregnancy terminated, according to Together for Yes, citing Dr. Jen Donnelly, a top obstetric consultant at the Dublin maternity hospital the Rotunda.

“The Eighth Amendment prevents me from providing complete pregnancy care to women when they are at their most vulnerable,” said Donnelly. “It prevents me for being there for women when they deliver, and it limits me from offering them further investigations such as postmortems, which may help guide their care in future pregnancies.”

Together for Yes is arguing for a “more compassionate Ireland” that will support, respect and protect women in their moment of need.

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Save the Eighth campaigners argue that repeal will lead to abortion on demand or selective abortion. Rónán Mullen, an independent senator and prominent abortion opponent, angered many last year when he said that abortion on demand would have saved the life of Savita Halappanavar, as she “wouldn’t have been in hospital because she wouldn’t have been pregnant.”

Storyful’s Mulligan said that, despite their smaller war chest, the yes-on-repeal campaign is succeeding in attracting more comments and longer engagement times for many of its postings, probably because so many include personal stories — for example, on Facebook, “In her shoes: Women of the Eighth” — that take longer to watch or read.

“There’s a lot more nuance to a video of someone recounting their own story, so it needs longer-form and people tend to interact more when there’s so much emotion involved,” Mulligan said.

The “no” side, meanwhile, has brought in outside expertise to advise its digital campaign, as Sheridan from Vizlegal has reported. Sheridan noted that Fuzati, a Texas-based Catholic marketing and tech company, was in Dublin in April and shared a Facebook photograph of its people with Protect the 8th representatives.

“The traditional problem with digital ads is that there is no regulatory framework for this stuff, which was well-flagged to the Irish government ahead of this vote,” he said. “The laws are 20 years old and completely out of date.”

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