The protests — relatively small but highly visible here in the Irish capital — are an emblem of the strong emotions as the country prepares to vote in late May on whether to retain the Eighth Amendment of the Irish Constitution, which bans abortion in nearly all circumstances and was itself enacted by a referendum, in 1983. (Abortion was illegal before 1983, but the amendment made it even harder to terminate a pregnancy, even to save to mother’s life.)

To the age-old debates around abortion — including questions of when life begins and of women’s control over their reproductive rights — the referendum has added a new dimension of concern about potential outside interference in the vote.

An ethics regulator recently ordered two abortion-rights groups, Amnesty International Ireland and the Abortion Rights Campaign, to return grants of $150,000 and $25,000 to George Soros’s Open Society Foundations. It said the money was a foreign political donation intended to affect the outcome of a referendum or election, and therefore banned.

But so far it does not appear that any anti-abortion groups have been asked to return overseas donations, despite reports that money is being openly raised on their behalf, particularly in the United States.

One American group, the Pro-Life Action League, told an Irish newspaper in 2012 that anti-abortion groups were raising hundreds of thousands of dollars to support Irish anti-abortion groups like Youth Defence, which has been linked to far-right movements in Europe.