Europe's biggest problem will be its current one: assimilation. What does being a "European" mean? As imperfect as identity politics may have been in the past, the Germans, French, Dutch and even the Swiss had a sense of self, if not always a sense of purpose. What are they now? If they are now the 25 "musketeers," can each be expected to work for the benefit of all rather than serve self-interest?
Individual European nations do not have a history of subordination of self-interest to the general welfare. Past alliances were mostly formed to advance the self-interests of a state or states entering into those alliances. When those interests were served (or rejected in war) the nation-states mostly continued as before.
Europeans are now being asked to subscribe to a creed grander than the United Nations, which has failed to usher in world peace. Twenty-five nations representing 450 million people have a lot at stake in this grandest of experiments. Past grievances have often overwhelmed future hope. The Irish Times' Hugo Hamilton referred to that checkered history in a May 1 article: "Each of the new states may have a communal future to a certain degree, but they each have their own ways of remembering the past."
Hamilton seems to be engaging in an act of faith (if not a leap) when he writes, "We see the bomb attacks in Spain as something that happened to us all. That collective sensitivity shapes our decisions about the future." Is that why Spain withdrew troops from the coalition in Iraq? Is that why France, Germany and England seem unwilling (or unable, as in England where liberal laws make it difficult) to deal with its non-assimilating Muslim population and the minority (we're told) among them who call for an Islamic union, by force if necessary?
Let's raise a glass with Dubliners to the larger European Union. But given the history of Europe, I wouldn't bet more than a pint of Guinness on a successful outcome.