Q. What is the purpose of the Nice Treaty?

A. The primary objective is to make institutional changes to the EU in advance of the admission of new member-states, mainly from central and eastern Europe.

The treaty's proponents argue that, in a Union of up to 27 states, the Commission's size should be limited and the voting weight of member-states should more closely reflect their share of the EU's population. But critics point out that the EU has already agreed to accept up to five new member-states and that the institutional changes will take effect in 2005 even if no new countries join by then.

Q. What are the biggest changes being proposed?

A. From 2005, the largest five member-states lose their right to nominate a second EU commissioner. Once the number of member-states reaches 27, no member-state will have an automatic right to nominate a commissioner. The Commission President becomes more powerful and will be allowed to move commissioners to different portfolios and, in some circumstances, to sack them.

The division of votes in the Council of Ministers, the body that makes most important EU decisions, will change. Larger countries will receive bigger shares of the votes, partly to compensate for the loss of their second commissioners. The treaty's opponents fear that the new distribution of votes will give too much power to the big countries, allowing as few as three member-states to block any decision.

A number of policy areas, including some trade negotiations and the appointment of the Commission, will no longer require the approval of all member-states. And groups of member-states within the EU will be allowed to forge closer co-operation with one another in some circumstances even if some other member-states do not approve.

The EU's Political and Security Committee will take charge of the 60,000strong European Rapid Reaction Force, which will engage in crisis-management, peacekeeping and peace enforcement.

Q. Will the treaty weaken Ireland's voice in the EU?

A. Statistically, yes. Under the present voting system, Ireland would have been 2.2 per cent in an enlarged EU. Under the new system, it would be 2.03 per cent. Ireland will also send fewer representatives to the European Parliament.

The Government points out that Ireland will still enjoy the same number of votes in the Council of Ministers as Finland and Denmark, both of which have bigger populations. And under the new system, Ireland's percentage of votes in the European Parliament will still be more than twice its population percentage.

Q. How will the treaty affect Irish neutrality?

A. Not at all, according to the Government. The newly created Rapid Reaction Force does not involve a mutual defence pact, and Ireland can refuse to send soldiers on any operation of which it disapproves. The Government says it will only take part in operations that are sanctioned by the United Nations.

The treaty's opponents argue that the involvement of Irish officers in the EU's permanent military structures will erode neutrality. They want the Government to introduce a further constitutional amendment ruling out any future involvement in a mutual defence pact.

Q. Will the treaty create a two-tier Europe?

A. Critics say that by making it easier for a few member-states to forge ahead with closer co-operation, the treaty will help form a core Europe of richer, more powerful states. They warn that new member-states from central and eastern Europe could find themselves in the second division, alongside older member-states that resist pooling more sovereignty with EU partners.

The Government maintains that the safeguards built into the treaty will ensure that enhanced co-operation cannot damage the integrity of the Union. They point to the strengthening of the Commission's role and the fact that any new sub-group would have to be open to new members. And they stress that enhanced co-operation will not apply to the single market or to security and defence matters.

Q. Is the treaty a step towards a federal Europe?

A. The treaty triggers a broader debate on the future shape of the EU that will culminate in a new treaty-making conference in 2004. Among the questions to be considered are how power should be divided between national governments and European institutions and the status of the Charter of Fundamental Rights agreed last year.

Some governments want sweeping changes that would make the charter the basis of an EU constitution, transform the Commission into an EU government and strengthen the role of the European Parliament.

Others want to return some powers to national governments and to set a final limit on the scope of the EU. But the debate is at an early stage, and it is difficult to predict what the final outcome will be.

Q. What happens if Ireland votes against the treaty?

A. The treaty must be ratified by all 15 member-states before it comes into force. Ireland is the only country to hold a referendum: most others will ask parliament to ratify the treaty.

If the referendum is rejected by voters, the Government could try to renegotiate the treaty and present a revised version to the electorate before the deadline for ratification at the end of 2002. But it was so difficult to find agreement between the 15 member-states last December that the scope for changes may be limited.

And there is, of course, no guarantee that the electorate would approve the revised treaty either.