Ireland is voting today on a referendum that, if successful, would make the country the first in the world to institute marriage equality by popular vote — a development that has alarmed marriage equality opponents around the world, including in the U.S.

On Wednesday, a group of U.S. and Canadian marriage equality opponents sent a “ message of caution to the Irish people ” warning them that the progress of LGBT rights in the United States has “produced serious and troubling consequences for religious freedom” and led “homosexual activists” to “censor, silence, coerce, and punish religious believers who criticize, oppose or resist them.”

Signatories of the letter, which was published on the website of the Catholic Action League of Massachusetts, include Brian Camenker of MassResistance, Human Life International President Shenan Boquet, John Horvat of the group Tradition, Family and Property, and John-Henry Westin, editor of the Canada-based LifeSiteNews.

The examples of supposed anti-Christian persecution cited in the letter include fines imposed on businesses that refuse service to gay and lesbian customers (which are the result of nondiscrimation laws, not same-sex marriage), a misprepresentation of an exchange in the recent Supreme Court marriage arguments about discrimination by religious schools, and the fact that employers have to provide spousal benefits to their legally married gay employees.

American groups seeking to stop LGBT rights initiatives abroad are increasingly leaning on the “religious liberty” messaging that they are using at home. In fact, the ways that LGBT equality and abortion rights supposedly trample on the religious freedom of their opponents will be the theme of the next World Congress of Families gathering in Utah.

From the Catholic Action League’s press release about the letter to Ireland: