The main issues to be dealt with in this week's Inter-Governmental Conference (IGC) are the so-called "leftovers from Amsterdam", but the institutional questions involved are far from trivial issues.
They are the size of the Commission, the allocation of votes to member-states at the Council of Ministers, and the roll-back of veto voting, and they all go to the heart of the relative influence of states.
Size of commission
Agreement in principle that the five larger member-states should lose their second commissioner as the Union gets larger has been complicated by a French determination to put a ceiling on the numbers in the Commission.
The accession of 12 new states, each with its own commissioner, was seen as likely to be hugely unwieldy. Ireland, Austria, Sweden and Portugal have held out resolutely against any agreement in principle to the loss of their automatic right to one seat at the table.
They argue that Brussels's legitimacy would be seriously undermined if each state did not have a commissioner.
To sugar the pill for the small states, the EU presidency has proposed deferring the imposition of a limit on Commission numbers, probably until 2010. It has also suggested automatic, equal rotation of membership, an offer that some diplomats argue is unlikely to be on the table again. It is a formula which has been gaining support since the Biarritz summit, although Spain and the UK have recently indicated that they too have reservations.
Vote reweighting
In the Council of Ministers member-states are allocated votes according to their size. The big four, Germany, the UK, France and Italy each have 10, while the balance of the 87 votes are distributed to the rest. Ireland has three. The large states have argued that successive enlargements in the past have tilted the balance unhealthily in favour of the smaller states.
Reweighting is thus certain to happen but the range of options reflects deep divisions. At one end of the scale is a radical recalculation, proposed by Italy, which would give the four large states 33 votes to Ireland's six. At the other is a minor adjustment of voting weights with the added stipulation that any majority must also reflect a population majority, the so-called double majority option, which is favoured by Ireland.
A solution is hugely complicated by the French insistence that, while they have some 24 million fewer people than Germany (82 million following unification), they should retain the same vote for reasons of historical continuity. Spain (36 million) also wants to be treated as an equal of the big four while Belgium is demanding parity with Holland, which has a population 50 per cent higher.
Qualified majority voting (QMV):
Some 45 issue areas in the treaties where voting is currently by unanimity have been singled out as amenable to a form of majority voting. But whether it's the Greeks on transport or the Belgians on the location of the EU institutions, every state seems to have a problem surrendering its veto on something. Ireland has made it clear that it will not give up its veto on taxation and still has reservations, though likely to be lifted, on social security harmonisation, the environment and asylum and immigration co-operation.
Taxation remains the most divisive, with Britain and Sweden also opposed to any change, while the Commission pleads that it is seeking changes only in areas of tax directly impinging on the functioning of the single market.
But senior diplomats point out that even if there is a perception of deadlock over some of the most controversial clauses, general agreement to move to QMV on a wide range of issues has been reached.
These include such issues as the financial regulations, key to reforming the Commission, structural funds, the environment, the appointment of senior officials, industrial policy, and anti-discrimination measures.
Reinforced co-operation
This is to be understood as the issue of how to make it easier for sub-groups of members to integrate faster than others on certain projects.
Broad agreement has been reached to reduce to eight the minimum size of such a group and to remove the right of an individual member-state to block such a development if it is approved by the Commission. Early fears that reinforced co-operation might lead to the emergence of a two-tier Europe have been allayed with a strengthening of the role of the Commission and other stronger safeguards. There is still disagreement, however, about whether to allow such groups in the security and defence field, with Ireland and the UK holding out most strongly against it.