Four EU treaties are being merged into a single, simplified text, incorporating a Charter of Fundamental Rights.
The president of the European Council, composed of heads of state and government, will serve for up to five years; this replaces the current rotating six-month EU presidency.
The new EU foreign minister will head a newly-created European diplomatic service. There will be greater scope for defence co-operation.
The European Parliament will get new powers.
The national veto will be abolished in some areas, but retained in others, such as tax, foreign policy and defence.
A new system of double-majority voting on the Council of Ministers requires participation by at least 15 member-states representing 65 per cent of the total EU population.
The EU will have a legal personality. States can leave if they so decide.
The European Commission is to be capped at two-thirds of member states, with seats being filled on a rotation basis.
Referendum Timetable
The new constitution must be ratified by all 25 member-states. Some are ratifying through parliament, others by referendum (Spain is using a combination of both):
Spain: Vote is this Sunday.
Portugal: Probable referendum, no date set.
France: May/June 2005.
Netherlands: May/June 2005.
Luxembourg: July 10th, 2005.
Ireland: No official date yet, but most likely the third week in October this year.
UK: Early 2006 most likely.
Denmark: Summer 2005 or spring 2006.
Czech Republic: Probably June 2006, in conjunction with parliamentary elections.
Poland: The government and opposition both want a referendum and differ only on its timing.
Parliaments in Hungary, Lithuania and Slovenia have already ratified the constitution. Italy's lower house of parliament approved it in January. The upper house has yet to set a date.
Deaglán de Bréadún