The European Union’s Lisbon Treaty comes into force on December 1 2009 with celebrations featuring EU leaders in the Portuguese capital, and proponents of the treaty hailing the day as historic and as bringing new benefits for the bloc’s 500 million citizens.
 
The Commission believes that the new treaty provides significant new benefits for citizens and will settle the institutional debate for the foreseeable future," the European Commission said in a statement.
 
"This will allow the European Union to fully concentrate on managing a smooth exit from the economic and financial crisis and pushing ahead with the 2020 strategy for greener growth."
 
EC President José Barroso said, "The Treaty of Lisbon puts citizens at the centre of the European project. I'm delighted that we now have the right institutions to act and a period of stability, so that we can focus all our energy on delivering what matters to our citizens".
 
The Treaty of Lisbon amends the current EU and EC treaties, without replacing them. It will provide the EU with a new legal framework and tools, advocates of the treaty say, to meet future challenges and to respond to citizens' demands.
 
"The Treaty of Lisbon will ensure European citizens have their say in European affairs and see their fundamental rights set out in a charter," the EC said.
 
"The EU will be better equipped to meet expectations in the fields of energy, climate change, cross-border crime and immigration. It will also be able to speak with a stronger voice on the international scene."
 
The EC said that an improvements brought by the treaty were a "a more democratic and open and accountable Union" – The European Parliament and national parliaments will now have a much greater say in the EU's decision-making process, and citizens will have the right to know what their ministers are deciding at the EU level.
 
All European citizens will be given the opportunity to influence proposed EU laws, the EC said.
 
The treaty, according to the EC, would mean a more effective EU – through effective and streamlined institutions. "Including swifter, more consistent decision-making on law and order issues, giving the EU greater ability to combat crime, terrorism and human trafficking."
 
It would also mean, according to the EC, more rights for Europeans – "the EU's values and goals will be set down more clearly than ever before. And the charter of fundamental rights will be given the same legal status as the EU treaties themselves."
 
The EU would become a more prominent global actor – new posts have been created as part of work to bring more coherence between the different strands of its external policy, such as diplomacy, security, trade and humanitarian aid.
 
"These improvements give the Union the capacity to deliver change, to make Europeans more secure and prosperous and to open up their opportunities to shape globalisation."
 
Swedish prime minister Fredrik Reinfeldt, whose country took over the rotating presidency of the European Council in mid-2009, said "A new era of European co-operation begins today".
 
"Today EU citizens are heading into a new era. Today is the first day for a more efficient, more modern and more democratic EU – for all citizens," Reinfeldt said.
 
The celebration in Lisbon were scheduled to be attended by the new European Council President, former Belgian prime minister Herman Van Rompuy and the UK’s Catherine Ashton, who becomes the EU's new-style foreign policy chief.
 
The treaty takes its name from Lisbon because it was there that the initial signing ceremony took place in 2007.
 
The process of approval of the treaty has gone through a number of obstacles, notably previous rejection by Irish voters – reversed in 2009 – and the prolonged reluctance by Czech president Vaclav Klaus to sign it.
 
Critics of the treaty continue to argue that it moves too many powers from individual member states to Brussels. Individual states will no longer have powers of veto over issues such as climate change, energy security and emergency aid, while unanimity will still be needed in tax, foreign policy, defence and social security, the BBC said.
 
The Lisbon Treaty: The milestones
 
June 2007: European Council mandate for an Intergovernmental Conference aiming at amending the existing Treaties
 
July-October 2007: Intergovernmental Conference
 
Approval of the Treaty at the informal European Council on October 18 and 29 2007
 
December 12 2007: Proclamation of the Charter of Fundamental Rights by the Presidents of the European Parliament (EP), the Council and the Commission.
 
December 13 2007: Signature of the new Treaty in Lisbon
 
December 2007 - November 2009: ratification procedures in all 27 EU member states
 
December 1 2009: Entry into force of the Treaty