Viviane Reding, the EU’s commissioner for justice and fundamental rights, has called for a Belgian-style mediator to be appointed following next year’s EU elections to try to form a Parliament coalition that will back the next president of the European Commission.

Speaking at the summer reception of the Union of European Federalists (UEF) on Tuesday (3 September), Reding said the 2014 elections would mark the start of “a new era” for the European Union as they would be the first to be held under the Lisbon Treaty, which entered into force in 2009.

Comparing the EU to a parliamentary democracy, she said the newly elected members of the European Parliament would need a mediator to appoint a new “government”, or European Commission after the elections.

Reding drew parallels between the formation of the new European Parliament and Belgium's practice of appointing a mediator to seek agreements and coalitions between the different parties, which leads to the selection of a prime minister.

“Who is going to decide what parties are going to be able to form a coalition in the European Parliament?" Reding asked. “The President of the European Council could be the one,” she answered, referring to Herman Van Rompuy, the current holder of the post who chairs the EU leader’s summits. In her view, two or three political groups could enter the coalition and back a new Commission president.

Such a procedure might seem common sense to EU outsiders. But Reding said it would require “a complete shift” in mentality on behalf of EU heads of states and government, “who might not be too enthusiastic to take this direction”.

Indeed, until now, the Commission president was appointed by the EU’s leaders behind closed doors, leading to obscure horse-trading deals. The appointee was then presented to the European Parliament for a simple majority vote.

This time things would be different, Reding said, because the Lisbon Treaty provides for consultations to take place with Parliament at the early stages of the selection process.

Article 17 of the Treaty stipulates that EU heads of states propose a candidate for the Commission “taking into account the elections to the European Parliament and after having held the appropriate consultations”. The chosen candidate will then “be elected by the European Parliament by a majority of its component members”.

For Reding, this means the end of backroom deals.

Herman Van Rompuy is open to taking on a mediator role, according to sources in the European Council. But for that to happen, each political family would first have to agree on a candidate for the Commission that has the backing of all their national affiliates.

This is easier said than done. In the socialist family, the current president of the European Parliament, Martin Schulz, emerges as a fairly consensual candidate for the January primaries. However it is still not clear who will lead the other two major political families – the centre-right EPP and the liberal ALDE. The Greens have announced an online primary to select their two champions.

But assuming each political family does agree on a candidate, the contenders would still need to be officially endorsed by their national government before flying to Brussels. In a concession to Ireland, which rejected the Lisbon Treaty in a 2008 referendum, EU countries have indeed maintained the privilege of nominating one delegate each to the Commission.

In practice, this may lead to awkward situations. For example, a national leader – such as Angela Merkel in Germany – would have to accept nominating a commissioner-candidate from the ranks of the opposition depending on the election results.

“If the socialists win, will Merkel accept to nominate Schulz?” said the European Council source.

Reding said she was skeptical that EU leaders would be willing to go that far but stressed that this is what the Lisbon Treaty implied. “If you sign a treaty, you should know what is in the treaty,” she said.