The two lead candidates in the race for the European elections have reacted vigorously to statements by Council President Herman Van Rompuy, who scorned the parties’ attempt to put forward candidates for the European Commission’s presidency.

Martin Schulz and Jean-Claude Juncker have denounced Van Rompuy’s statements over the weekend, saying he cannot circumvent voter choice, and that the new Commission President will need a firm majority in the next Parliament.

According to Jean-Claude Juncker, the former Luxembourg Prime Minister campaigning for the centre-right European People’s Party (EPP), “the democratic toothpaste is out of the tube with the election of a lead candidate”.

“The old days, when a Commission president was elected by diplomats in backrooms are finally over,” he told the Süddeutsche Zeitung.

Earlier, Van Rompuy had scorned the parties’ attempts to put forward a lead candidate for the European elections in a bid to win the top seat at the Commission. “The difference between the Parliament and those who really decide is very clear to citizens,” the Belgian said.

The next president of the EU executive will be nominated by EU leaders, but the European Parliament will elect him or her through a vote, a novelty brought about by the Lisbon Treaty (article 17.7, TEU).

Over the past months, Van Rompuy has consistently objected to the procedure, in what is a surprisingly militant position for an otherwise abiding diplomat.

Martin Schulz, the candidate for the Socialists and Democrats, told the Süddeutsche that Mr Van Rompuy’s declarations were the expression of his “own opinion, based on his interpretation, to fit his job description. Many in the European Council see this issue [of a common candidate] differently. Most importantly, the European voters see this differently.”

“We were disappointed to hear this message from Mr Van Rompuy,” said Julian Priestley, the former secretary general of the European Parliament who leads Schulz’ campaign. “It seems he continues to deny the will of Europe’s voters and dismiss the democratic legitimacy of the upcoming elections,” Priestley told EURACTIV.

The five candidates for the job also include the Belgian liberal Guy Verhofstadt, the Greens’ Franco-German duo José Bové and Ska Keller, and the far-left Greek candidate Alexis Tsipras. All are currently touring EU member states, supporting national parties in their bid to get voters to the polls on 22-25 May.

“Mr Schulz and I are touring the whole of Europe, to make clear the stakes of the elections,” Juncker stressed, saying “Every citizen can co-decide the direction of Europe for the next five years.”

European parties have an informal agreement that the party winning the most seats can put forward its candidate for the EU Executive.

Latest polls put the EPP in the lead with 222 projected seats, followed by the socialists with 209 seats. The liberal ALDE party is credited with around 60 seats, the far-left GUE-NGL around 50 seats and the Greens and Conservatives with about 40 seats each.

Crunch time

Between 22 and 25 May, European citizens will elect a new European Parliament, made up of 751 members. For the EU executive however the 27th May will be the decisive date, with EU heads of states meeting in Brussels to designate the new Commission President.

In Parliament, the designated Commission chief will need the backing of at least 376 MEPs in order to get “elected”. Most likely, a grand coalition will support the winning candidate – whether Martin Schulz, Jean-Claude Juncker or someone else. A coalition of socialists, liberals, greens and the far-left could provide Schulz with a majority but polling shows that this is highly unlikely.

However, political parties have always kept the door open for coalitions to support a candidate. “We will then work to build the coalition which will have the necessary majority to elect Martin Schulz and to put the EU on a new path, strengthened by this new democratic underpinning,” Priestley said.

Ultimately, all will depend on the endorsements of the European Parliament and the 28 EU heads of states. So what will happen on 27 May?

Morning : The European Parliament’s conference of presidents meets in Brussels, in an extraordinary session. The meeting will include lead candidates Martin Schulz and Guy Verhofstadt, as well as political heavyweights like Joseph Daul (EPP) and Rebecca Harms (Greens).

: The European Parliament’s conference of presidents meets in Brussels, in an extraordinary session. The meeting will include lead candidates Martin Schulz and Guy Verhofstadt, as well as political heavyweights like Joseph Daul (EPP) and Rebecca Harms (Greens). Afternoon : Traditionally, the pan-European parties meet up in pre-election summits of their own member parties. These pre-election summits are attended by heads of state – a crucial moment for the parties’ leadership and the candidates’ entourage to get an endorsement on a potential deal in Parliament.

: Traditionally, the pan-European parties meet up in pre-election summits of their own member parties. These pre-election summits are attended by heads of state – a crucial moment for the parties’ leadership and the candidates’ entourage to get an endorsement on a potential deal in Parliament. Evening: The European heads of state are gathered by the European Council president, Herman Van Rompuy, for an “informal dinner” to discuss the elections. Key question: will the EU leaders stand by the process of ‘Spitzenkandidaten’ or not?

If all goes according to plan, political parties will first have to come to an agreement and gather the necessary votes in Parliament. Then, the heads of states will give their blessing to the candidate.

But ‘dark-horse candidates’ could also emerge at the last minute if none of the leading ones find the assent of EU leaders. These might include the managing director of the IMF, Christine Lagarde (centre-right) or the former president of the World Trade Organisation, Pascal Lamy (Socialist).

Those defending the single candidate procedure do not want to believe in such a scenario. “Already 27 out of the 28 Heads of Government have endorsed this system,” Priestley said. “It would be a travesty if they went back on their commitments in June.”

In case a ‘dark horse’ candidate emerges, it could bring the institutions into a deadlock and put Van Rompuy head-to-head once more with the pan-European parties.