Explaining the agreement reached by the two candidates, ALDE party leader, Sir Graham Watson, said the two politicians would jointly lead the electoral campaign "on an equal footing".
Verhofstadt will run for the post of European Commission president to replace the incumbent José Manuel Barroso, while Rehn wil run for one of the other senior EU posts in economic or foreign affairs.
The move has surprised a few EU pundits who say Olli Rehn, the EU's economic and monetary affairs commissioner, has stepped aside to let Verhofstadt, the leader or the ALDE group in the European Parliament, take the lead, and secure for himself a high-level post in the new Commission.
In December, Rehn appeared to be in pole position to lead the EU liberals in the 2014 election campaign, after he secured the support of 14 liberal parties.
The agreement was hailed by some liberal MEPs, such as Andrew Duff, a Briton, as a “a great victory for Guy and for his campaign skills, which he brings to the fore. It is a victory of his ideas and the programme he proposes, too".
“There is a critical decision to make on a Europe along the federalist track. The outcome of this process, as well as the manifesto that we, ALDE, decided on, clearly shows that the majority of ALDE is prepared to stick to the idea of a reinforced Europe,” Duff continued.
Verhofstadt, the former Belgian prime minister, is one of the EU’s most avid euro-federalists. In 2005, he published a book on closer EU integration, ‘The United States of Europe’, and he is one of the driving forces behind the Spinelli Group of federalist MEPs, launched in 2010.
Last month, Verhofstadt faced criticism from members of the Dutch liberal party, including the former Dutch EU Commissioner Frits Bolkestein who accused him of “barking at the moon”. Bolkestein added that “Europhiles pose a greater danger to Europe than eurosceptics”.
Bolkestein’s VVD party, however, got the former commissioner back in his corner and asked him to withdrew his comments. VVD is amongst the member parties endorsing Verhofstadt.
The motion for a resolution proposed to the ALDE party’s bureau by Watson will be discussed in the coming days and submitted to members at the electoral meeting in Brussels on 1 February, a spokesperson said.
According to Duff, the magic number of MEPs to agree on a candidate in Parliament stands at 376. “Rehn was never going to achieve this, but Guy could rally support from the broad left of the EP, as well as of classical liberals,” he added.
“In my view, he will bring a great deal of energy to the campaign. The campaign will also be polarised: federalists versus nationalists. And this has an effect in member states: it pushes the UK’s LibDems to strongly support the European Union.”
Together against populism
Verhofstadt said he was delighted that through the work of Mark Rutte and Christian Lindner, they had found a compromise formula that would enable liberals to work together and allow the two former opponents to contribute respectively to the campaign and deliver a strong showing from the Liberals and Democrats in the new Parliament.
“Pro-Europeans are under attack in a number of Member States so it is all the more important that those who still believe in the European Union stand together to combat the reactionary forces of nationalism and populism that is spreading doubt and fear in the minds of Europe’s citizens,” Verhofstadt said.
“The Europe of today is clearly not delivering for the citizen. We must elucidate a new and positive vision for the EU of tomorrow that builds on what has been achieved over the past 60 years but works more efficiently and effectively," he added.