The Minister for Transport, Mr Varadkar, in commenting on whether a referendum will be necessary for Ireland to sign up to the fiscal compact is reported to have made the commonplace point that
There’s only one reason why you have a referendum and that’s where there is a requirement to change the constitution.
Em, not quite.
Apart from a political view that a referendum might be desirable in any event, there is a particular mechanism in the Constitution of Ireland for holding a referendum, even when a measure does not require constitutional amendment. This is set out in Articles 27 and 47, whereby one-third of the Dáil and a majority of the Seanad could petition the President to decline to sign and promulgate a Bill “on the ground that the Bill contains a proposal of such national importance that the will of the people thereon ought to be ascertained.”
The detailed provisions of Article 27 envisage that if such a petition were successful, the will of the people could be ascertained either by referendum (in which at least one-third of those on the register would have to vote “no” in order to veto, by virtue of Article 47) or, in effect, by a general election.
I guess the fiscal compact itself may not in fact be a Bill, but presumably the detailed fiscal provisions of the agreement will have at least that legal form. Apart from whether the required numbers of TDs and Senators would line-up for the petition which Article 27 envisages, whether or not this mechanism will be applicable seems to me, as a non-lawyer, to turn on whether the Bill in question is a “Money Bill”. Money Bills appear to me to exempt from Article 27 (reading back to Articles 23 and 22) but I may be mis-reading that, so perhaps we might get some legally informed views in comments.