EU leaders have reached agreement on a European constitution at their summit in Brussels.
Click on a question to find out more about the constitution - and the disagreements:
Does Europe need a constitution?
The EU now has 25 members, but it is still working according to rules that, though modified over the years, were designed for the original group of six. At a summit in Laeken, Belgium, in 2001, EU leaders called for moves to make the union "more democratic, more transparent and more efficient".
The constitution, actually a "constitutional treaty", will replace earlier EU treaties. It is a single document saying what the EU can and cannot do.
Its supporters hope it will give the EU a clearer sense of its purpose, one that the public can easily understand.
But the constitution is unlikely to come into effect for two years or more. There is also a possibility that it will not be ratified by one or more of the 25 states.
What were the main sticking points?
The biggest was about voting weights in the EU Council of Ministers.
At the December 2003 summit, Poland and Spain were dead against a proposal in the draft constitution that said a vote would be passed if it had the support of 50% of member states representing 60% of the EU's population.
They argued in favour of an earlier system, agreed at Nice in 2000, which gives them almost as much clout as the biggest countries - France, Germany, Italy and the UK.
In the end, a compromise proposal was adopted of at least 15 member states representing 65% of the EU population. This will apply from November 2009.
Another dispute raged over the number of commissioners each country should have.
The draft constitution proposed that there should be 10 voting commissioners in total, and that the posts should be held in turn by the 25 members.
However, a number of small countries insisted on the principle of one country, one commissioner - even in an enlarged EU.
Leaders finally agreed to cut the number of commissioners to 17, starting in 2014. They will be selected on a rotating basis and will serve for five years.
On religion, a number of countries, including Poland, Spain, Malta and Ireland, wanted the preamble to the constitution to include a reference to Christianity, or the Judaeo-Christian tradition.
This was opposed by other countries which believe in a rigid separation of church and state.
The final text says that the EU "draws inspiration from the cultural, religious and humanist inheritance of Europe".
The veto will remain in key areas including foreign policy, defence and tax, as Britain and other countries wished.
There were also disagreements over a mutual defence clause which has now been inserted in the draft constitution.
Neutral countries had said an obligation to come to the aid of another EU country when it is attacked was not compatible with their neutral status.
Have there been any big steps forward during the months of debate?
A proposal on defence co-operation by Britain, France and Germany won general backing at a conclave of foreign ministers at the end of November.
This allows the EU to acquire a small military planning capability to enable it to take on operations independently of Nato. However, the constitution emphasises that Nato remains the foundation of European security.
What else is in the constitution?
It contains everything from grand "vision" statements on Europe's future to specific details about how member states can leave. Some of the content has already appeared in other EU treaties, but other parts are new.
An EU foreign minister: This new post rolls into one the existing posts of external affairs commissioner and foreign policy chief. The foreign minister (some countries do not like the word "minister" and have proposed alternatives) will be a member of the European Commission, but will be answerable to the Council of Ministers.
Presidency: A permanent president for the Council of Ministers is set to replace the current system whereby each member state in turn holds the presidency for six months. A number of countries, mainly the smaller ones, say the new proposal favours the bigger countries, and want rotation to continue.
Charter of Fundamental Rights: The EU's charter is set to become part II of the constitution.
European Parliament: More power for the parliament, so that it votes on nearly all EU decisions and has an influence on the choice of the president of the commission.
Exit clause: The draft lays down for the first time a procedure for leaving the Union.
Suspension clause: It also sets out a system for member states to agree to suspend a country which violates the Union's basic principles.
Who wrote it?
Former French President Valery Giscard D'Estaing's 108-member convention agonised over the draft for a year and a half. The original draft was also modified with recommendations from the EU governments.
The convention members were drawn from EU governments, parliaments and the European Commission.
Does the word "federal" appear?
The word "federal" does not appear in the text, because it is prone to different interpretations and alarms eurosceptics. Instead the document talks about building European ties "in the community way".
The text also says the peoples of Europe are determined to be united in an ever closer fashion and to forge a common destiny.
How will it change my life?
It probably won't, at least not in an everyday sense.
Voters won't notice much difference in the way Europe operates, although the president and foreign minister could in time have very high-profile jobs.
February 2002: Convention starts work
June 2003: Draft submitted to EU Thessaloniki summit
Autumn 2003: Intergovernmental conference debates constitution
December 2003: Brussels summit fails to agree final text
June 2004: EU leaders reach agreement
The constitution could also bring some European issues closer to home, as national parliaments vote on whether to try to block specific pieces of European legislation.
And some decisions will be taken in a more transparent way, so people will know how their governments voted on particular decisions.
Who does not like it?
Eurosceptics fear too much power is being handed to Europe, while euro-enthusiasts complain that a chance was missed to further develop the EU's existing federal elements.
There are concerns in some quarters that the new president and foreign minister could become too powerful, undermining the sovereignty of member states. The European Commission also sees the president as a threat to its own authority.
Some have also questioned whether the new Europe will really be any more democratic than the old one - even though the constitution was partly conceived as a tool to cure the EU's "democratic deficit".
When will the new constitution become law?
The 25 member states are meant to ratify the constitution before the end of 2006.
Some countries will be holding referendums on whether to ratify it. If any country votes No, there may be a delay while a solution is found.
One option would be to wait for the country to hold a repeat referendum, in the hope that it would vote Yes second time round.