"The eventuality of an Irish rejection would be a problem not only for the French presidency but for Europe," Sarkozy said. "It's for the Irish to decide on this, but what Madame Merkel and I have decided is that, whatever happens, the reaction will be a Franco-German one."

"Brown could come under strong pressure to abandon the treaty's ratification, now in its final stages in the British Parliament, and declare the EU's attempts to reform itself over," Hugo Brady, research fellow at the Center for European Reform in London, said in a policy paper.

"If the treaty is abandoned, EU countries are likely to give up on attempts to ratify wide-ranging reform treaties, preferring instead the ease of working more closely together through avant-garde groups on matters such as defense, foreign policy or taxation."

integrationists have been making noises about enhanced cooperations, two-speeds, core Europe, Europe with variable geometry, etc since the Treaty of Amsterdam (and getting louder in the last couple of years) and if the Treaty of Lisbon fails that will be the only way forward and it will be taken.

But diplomats would struggle to give the Irish any genuine commitments to address the issues of concern raised in the Irish referendum campaign, since most fall outside the scope of the treaty.

...

The most likely option is that the treaty would be abandoned and that the EU would attempt to revise its current arrangements only when it prepares to admit the next nation due to join, Croatia, in 2011 or 2012.

Andrew Duff, Liberal Democrat spokesman on constitutional issues in the European Parliament, said that a rejection of the treaty in Ireland would mean its demise.

...

He also said that ideas of forming an advance guard of countries excluding Ireland would be difficult without the Lisbon treaty because there are fewer possibilities to do so under the existing Nice Treaty.