A New Referendum?

My presumption has been that any set of “fiscal union” measures of the type mentioned here will require a referendum. Far more trivial international agreeements have required them, so surely this would too. Eoin reckons it can be avoided via some Lisbon-related maneuver.

I’m not a constitutional expert but some of our readers must be. What do people think? Can we get some concrete cites to the relevant articles or protocols.