This result shows how much has changed in Ireland over the past few decades, and in particular, how much the influence of the Catholic Church, which once controlled all aspects of life in the republic, has waned. It has only been 22 years since homosexuality itself stopped being a crime in Ireland, and a decade or so longer since divorce became legal. Of course, the Church Holy Roman and Apostolic's influence still weighs heavily in one conspicuous area: abortion remains strictly illegal in Ireland, with several referenda in the past decades failing to reverse this. It is, to say the least, not at all clear that this would be repeated in any future referendum. (On the other hand, the experience in the US has shown that it is possible for a liberalisation in gay rights to occur alongside a rolling back of womens' reproductive rights, so legalised abortion in Ireland is by no means inevitable.)
The decision's impact will spread beyond the Irish Republic; calls for reform in Northern Ireland, the only part of the United Kingdom where same-sex marriage is illegal, are likely to be strengthened (though still face an uphill battle, with the conservative Democratic Unionist Party coming increasingly under evangelical Protestant influence. Considerably further afield, Australia is another place where this may have an impact. Australians famously like their politicians to be more conservative and moralistic than they themselves are, which has been reflected, as recently as a few years ago, in both major parties being against same-sex marriage. The vein of religious conservatism that animates this opposition, meanwhile, stems largely from Irish Catholic conservatism (the Prime Minister, Tony Abbott, is an conservative Catholic whose political views stem largely from the ultra-conservative, Democratic Labor Party, which emerged when the Catholic elements in the ALP left, citing creeping Communist influence in the party); while it is possible that Australia will remain as a sort of Galapagos of the Irish Catholic Right circa 1950, preserving this otherwise extinct culture in the way that a 19th-century dialect of English remains alive on the South Atlantic island of Tristan da Cunha, the fall of the Old Sod to secular modernity could have an effect.