The IAI website appears to be down, but there was a very interesting document located there, that I have managed to find elsewhere (PDF) .
It all boils down to Declaration no. 30 in the annexes which states:
Declaration no. 30 annexed to the CT reads: âThe Conference notes that if, two years after the signature of the Treaty establishing a Constitution for Europe, four fifths of the Member States have ratified it and one or more Member States have encountered difficulties in proceeding with ratification, the matter will be referred to the European Council.â? This statement is important for various reasons.
The first concerns the convening of the European Council: if at least four fifths of the member states (that is twenty) have ratified the Treaty within two years of signature, the European Council is obliged to meet to examine the situation. Of course, the European Council can meet even if this quota is not reached, however the meeting must take place if it is. Therefore, twenty ratifications of the CT are an important threshold. Reaching it does not mean that the Treaty enters into force, as some would have liked. It does however oblige member states to meet and work together loyally and in good faith towards a positive outcome.
Second, the Declaration does not make a distinction between which states ratify the CT and which do not. It simply refers to the four-fifths threshold. Therefore, each member state has the same weight, regardless of its size or seniority in the European Union. These factors will undoubtedly come into play when trying to find a way out of a ratification crisis, but in terms of the procedures provided for in Declaration no. 30, all member states have
equal standing.The third consideration concerns the two-year deadline. A twofold
obligation for the member states stems from the Declaration. First of all, member states must plan internal ratification procedures so that they are completed within two years of the signing of the CT. Secondly, and this is the point that interests us most, no member state may decide to stop the ratification process because, for example, another state has chosen not to ratify. The Declaration requires that the process go ahead.In fact, this is the only way to see whether or not the threshold of 20 ratifying states has been reached within two years. The only exception would be if more than five states had already rejected ratification. In that event, since the twenty state threshold could no longer be reached, a state would be entitled to suspend the ratification procedure. In all other cases, the obligation
outlined above remains valid.
Read the whole document, its short and worth a read.