Barnier gave the speech during Europe Day celebrations at Berlin's Humboldt University.
"One day a future president of the European Union, whoever he or she will be, should both preside over the European Council and chair the European Commission," he told students.
Sources close to Barnier said his idea had nothing to do with the work or competence of those who currently occupy those positions, Herman Van Rompuy and José Manuel Barroso respectively.
They added that such a merging of roles would make the EU more "readable", facilitate communication between the EU's leadership and the general public by giving the Union a more obvious "face", and boost the democratic legitimacy of the EU as a whole.
Piotr Maciej Kaczyński, a research fellow at the Centre for European Policy Studies, suggested that such a fusion would significantly improve the Union's visibility by reducing the current multiplicity of EU presidents (see 'Background').
"The European executive would be reinforced. And it would probably be more effective," Kaczyński said.
No reform needed
The idea of having a single EU president is not new. It was mentioned during the Convention on the Future of Europe in 2002, which later drafted the ill-fated constitution for the European Union.
Barnier's suggestion is similar in spirit to a proposal by UK Liberal Democrat MEP Andrew Duff to draw up pan-European party lists which ought to be headed by potential commissioners.
A key distinction, however, is that Barnier's proposal would not require reform of the EU treaties. He said in his speech that "the drafters of the Lisbon Treaty were careful not to rule out this major and symbolic step forward".
Researcher Kaczyński suggested that combining the two posts might be possible in 2014. That year the new Commission president would be drawn from the winning political group in the European parliamentary elections and the Council president's term would have to be renewed. "Why not, in this case, choose the same person for the two offices? Nothing forbids this in the text," Kaczyński said.
In not requiring possibly long and contentious treaty reforms, Barnier's proposal resembles European Parliament President Jerzy Buzek's idea of having European commissioners head national electoral lists and attempts by the European socialists – the second biggest group in the Parliament – to choose a pan-European 'winning candidate' for Commission president in the 2014 elections.
Federalist overtones
Barnier's speech also suggested more long-term reforms that would require a change to the treaties.
He said the EU's democratic legitimacy and connection to national public opinion could be improved by having the powers of the Commission and Council president "vested in them by a Congress comprising both the European Parliament and representatives of the national parliaments".
Barnier said Europe must aim to become a "Federation of Nation States," an expression which highlights the tension in dividing powers between the EU and its member states.
Somewhat paradoxically, he added that "we are not a single European people. We cannot be a European nation. There is no question of a federal state which would take the place of the nation states or the regions".
Barnier concluded his speech with an "appeal to the 27 heads of state and government and to President Herman Van Rompuy. This unity is in their hands".
