The public should not be voting on European treaties, and this episode just demonstrates how right the French and Dutch were in changing their ratification process. As we well know, European treaties are often a couple of hundred pages long and are intended to amend the treaties before it. Most in the European public are apathetic to the operation and purpose of European integration and the Union. This means that the Irish electorate has to rely on media coverage, which we know is often skewed in an anti-Europe direction.
The thing is, European "treaties" are establishing much more than your standard treaty institution - the European Union is being established as a superstate. With legislative, executive and judiciary branches, that indeed supersede most legislative activities in local parliaments, and becomes court of last resort over any court decision.
Such an important body needs legitimacy and approval from citizens ; without being asked for it, many will feel manipulated and dictated too, normal sentiments played upon by national media and unscrupulous politicians. Strong constitutional changes need popular approval.
Democratic institutions needs at some points to appeal to popular approval, at least to found their legitimacy. That's why Europe will need an EU-wide popular assent, or states will continue to undermine it, like for example Sarkozy regularly does. A body of treaties that has been repeatedly refused needs to be changed - a message the governments don't want to hear.
The approval needs not be a referendum ; but an European Parliament elected with constitutional powers as an major campaigning point could have that legitimacies. Governments, which are still systematically elected on national platforms, with EU policies an afterthought, don't have that legitimacy. Un roi sans divertissement est un homme plein de misères