I wouldn't say 'terminally' but I would say 'critically'.
Lisbon I had one unique component. As usual it had the usual suspects (Sinn Féin, the hard left, Coir) most of whom the electorate would not touch with a bargepole, a fact shown again in the difficulty
SF candidates had in getting transfers in the locals and Europeans. The new element this time was Libertas and Ganley, who went into the campaign as an unknown, someone who seemed to have little in common with the hard left or the hard right, and so who added a new credibility to the No side. There was a feeling of 'he's a successful businessman, an ex-FFer, so if he is against it it must be bad.'
For many voters who frankly hold their noses at voting on the same side as the looney left or the hard right, Ganley gave an opt out.
The last year had seriously weakened Ganley's perceived middle of the road neutrality. Revelations about his role in Albania, his links with some in the US, and his closeness to the Catholic right, plus the collection of often repulsive nutters he pulled in to run for Libertas in Europe (homophobes, anti-semites, extreme religious fundmentalists, etc) removed his middle of the road appeal. That problem was magnified severely when not alone did he not win a seat - and in the process engaged in quite vicious and unfair smearing of rival candidates - but Libertas Europe-wide was humiliated, winning only 1 seat, for an extreme anti-semite French aristocrat.
The defeat of Libertas means that in Lisbon II the No side will be much more of a traditional hard left/hard right variety. As canvassers have often found,
SF in European referenda lose as many votes to the No side as they bring to it, with a lot of people saying 'I cannot bring myself to vote the same way as Sinn Féin on something' - it is the same mantra that is heard in every election and referendum. (
SF openly admit that problem privately, which is why they don't get a proportional number of transfers to their first preference votes.)
Another problem will be that the ability of Mary Lou and Patricia McKenna to claim to speak on behalf of the people of Ireland will have been undermined by the fact that both were rejected. In fact
SF had a pathetically bad result in the Republic, a fact that has escaped attention because
FF and the Greens did woeful. But
SF themselves admit that on those results a number of their TDs would lose their seats in a general election. They are seriously worried about that.
The No side was not done terminal damage. But the damage was major. The only prominent No campaigner in the Euros to come through unscathed was Joe Higgins who against predictions (and to his own horror, as he never wanted to) won a seat. The No side is seriously weaker, with Sinn Féin, Patricia McKenna and Kathy Sinnott all badly weakened, and Libertas destroyed.