Ireland is a much more liberal and secular country than it has been in the past, but religion still plays a bigger role in Ireland than in some other European countries (though it's debatable whether or not this is due to conservative religious views being widely held, or if religious conservatives are just well organised and good at promoting their message). The idea of "Christian Europe" is alive in some quarters (though my impression that defining Europe as Christian is limited to a few groups), and I have even heard Dana (who almost got to run for the Presidency, but didn't even have enough support to force an election) talking on RTÉ radio about how the EU "discriminates" against Christians. It was a very strange debate, with her opponents rightly rubbishing her claims, but they also pointed to the Catholicism of some of the EU's founding fathers, as if the EU can (and should) be claimed as some sort of Catholic creation.
I would stress that this is a very minor issue; most concerns are based on sovereignty issues (tax & defence) rather than religion - Coir didn't really mobilise many voters to the No side based on family law issues (a stance which directly contradicted the Church's position), though it was able to protray itself as a success in the light of a No victory.
(Still, I would have thought that the response to such arguments would be based more on the "faith should be divorced from the state" line, since Ireland hasn't exactly had a great experience under official and semi-official Churches, both Anglician and Catholic.)
Now the archbishop of Ireland has backed a more positive view of Europe, and even considers the duty of the Church to set right the misinformation of "fundamentalist Catholics" (his words). To be fair, the Church has generally been pro-to-neutral on Europe, but its silence when misinformation on family law is being spread has meant that the EU has been protrayed mostly by small groups as being hostile to Catholic interests (perhaps some form of religio-patriotism to boost the profile of the conservative side on family issues?).
So an ethical issue for those who believe in the separation of religion and politics (as hard as it is to do so): do religions have a duty to intervene in a political debate when groups outside their control are using misinformation of the facts and of the religion's position to influence politics?
And if the Catholic Church steps in to dismiss anti-Lisbon Treaty claims, will this have much impact on Libertas, which Ganley is turning increasingly into a right-wing traditionalist/religious political platform?