Very thoughtful post by Henry Farrell in Crooked Timber.
First, they have to get a majority vote in a referendum in Ireland. This is thanks to a legal ruling (the Crotty ruling) that Treaty texts which have constitutional implications (which any Treaty involving significant further integration obviously would have) require popular assent in a referendum. Given popular anger at the way that the bailout has been structured, I imagine that the chances of Ireland voting ‘yes’ to any new European initiative are close to zero.
Yet even if somehow the Irish people could be persuaded to say yes to some initiative – perhaps because it put in place a more equitable system of fiscal transfers in the case of crisis – it would have to pass through the second veto point – the German Constitutional Court. The Court has made it clear in recent rulings that it is not prepared to countenance major new initiatives that might e.g. shift responsibility for decisions over fiscal policy to the EU level. In other words – any more equitable system of economic governance is likely to be vetoed.
It is extremely hard to envisage Treaty changes that could get a yes vote in Ireland. It is next to impossible to imagine any new Treaty that could both get a yes vote in Ireland, and survive scrutiny in Karlsruhe. Hence – the process of ‘ever closer union’ through Treaty change is effectively dead. One can imagine other mechanisms of change (drift, policy incrementalism, ECJ rulings) coming into play, but they are unlikely to result in any very obvious changes except over the very long run.