DUBLIN, Ireland – One day before Irish voters go to the polls to determine whether the country will lift its near-total ban on abortion, monitors say that attempts by Facebook and Google to regulate political advertisements on their platforms have not worked. Earlier in May, concern over unregulated online advertising – including by international organizations – prompted the online giants to restrict or remove referendum-related ads on their sites.

"We're still seeing money spent to target Irish voters online. In many cases the location, identity and intent of advertisers remaining unknown. This shows that self-regulation does not work," Liz Carolan, co-founder of the Transparent Referendum Initiative (TRI), a group that monitors online advertisements relating to the referendum, said in a statement.

International involvement

In Ireland, as in the United States, it's illegal for foreign entities to contribute to political campaigns. It is not illegal, however, for them to target Irish voters online, and TRI's work reveals some American organizations were doing just that.

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As of late April, the Initiative had publicized more than 20 abortion referendum-themed ads by entities based outside of Ireland. Of them, CBS News was able to trace 14 with a relative degree of certainty as coming from the United States.

While some were created by media companies, others, like one posted by a group called Chicago for Repeal, which is made up of "Irish people and their allies living in Chicago," targeted people in Ireland or friends of friends of group members, urging them to vote to repeal the 8th amendment.

Two ads from the New York-based anti-abortion group Expectant Mother Care-EMC FrontLine Pregnancy Centers, which describes itself on its website as "fighting for life in NYC -- the Abortion Capital of America" promoted and publicized a recent anti-abortion rally in Dublin.

"This same person who has spent the money to promote this post targeted at Irish voters," Craig Dwyer, who cofounded TRI along with Carolan, said of the New York group, "could not (legally) spend money to donate to a campaign."

Despite the moves by Facebook and Google to restrict referendum-related advertisements from outside of Ireland, however, analysts on Thursday said foreign influence on the vote hasn't necessarily been limited.

"Even after the ban, we continue to see ads from anonymous or untraceable pages where we've little to no information about who they are or who's paying for the ads" said Killian McLoughlin of University College Dublin's Geary Institute, who is examining data collected throughout the lead-up to the vote.

Ireland's abortion ban

In 1983, the Irish people voted to add an amendment to their constitution that formally equates the "right to life of the unborn" fetus to the "right to life of the mother." Known as the 8th Amendment, the clause totally bans abortion on Irish soil apart from in cases where the pregnant woman can prove she will die or kill herself otherwise.

Though the campaign to repeal the 8th began almost as soon as the amendment was created, it gained steam after the 2012 death of dentist Savita Halappanavar, who was refused an abortion as she was miscarrying and eventually died from septic shock. Protests broke out and pressure mounted until the beginning of 2018, when the government committed to holding another vote on whether to strike down the abortion ban.

The new referendum is scheduled for May 25, and polls currently suggest there is a majority among Irish people in favor of repealing the ban.

Regulating political ads online

"Without any regulation, effectively the online political arena is the Wild West," Irish parliamentarian James Lawless tells CBS News. He has written a bill which would require that online political ads clearly indicate who paid for them.

The Online Social Advertising and Social Media (Transparency) Bill 2017 is still working its way through Ireland's legislature, but regardless of its success, Lawless believes something must be done to protect the integrity of Irish democracy.

"If we don't get my bill passed, if we don't get anything else passed, we're completely unregulated. It's a complete free for all, and it's effectively and invitation to all third parties that may have an interest to get their hands dirty and walk in and play by the rules that aren't there."