Verhofstadt himself didn't mention it openly, but in his speech to open the congress he said that he wanted to break "the unholy alliance" between the Socialists & Democrats (S&D) group and the center-right European People's Party (EPP) in the parliament.

Last week, the current parliament chief, S&D's Martin Schulz, said he would not seek a third 2.5-year term. His soon to be vacant position is coveted by the center-right EPP.

The EPP, the assembly's largest group, says that it should get the presidency by virtue of the gentleman's agreement by which the EPP and the S&D traditionally split the parliament's 5-year term in two.

In Warsaw, Verhofstadt said that he rejected "a Europe mismanaged by the two big old parties" and wanted to put an end to "back room deals and mandates without a vision or without a project."

The EPP will choose its candidate on 13 December. While Italian MEP Gianni Pittella said he was running for the S&D.

Verhofstadt is "the top top candidate" for the position Czech MEP Pavel Telicka told EUobserver, arguing that he was a "heavyweight" in the parliament and "more inclusive" than Schulz or the candidates to replace him.

He added that his leader would be "not just a speaker" and would "not be the defender of Alde's positions in the same way as Schulz has been the defender of S&D's positions."

But beyond principles, the Alde is also trying to increase its influence.

The party's president, Dutch MEP Hans van Baalen, pointed out that the EPP already had the top jobs at the European Council and European Commission, with Donald Tusk and Jean-Claude Juncker.

"There should be a liberal who is president of the European Parliament and there is one who can do it, it's Guy Verhofstadt," Van Baalen told EUobserver. "We'll give him all the support needed."

Although Verhofstadt, a former Belgian prime minister and recently appointed the parliament's Brexit coordinator, is a well-known figure, his group is only the fourth largest in the parliament.

With 69 Alde MEPs, Verhofstadt needs 307 more votes to win the presidency, and will only run if he gets the backing of other groups against the EPP and the S&D.

'His moment is now'

Alde sources told this website that the Green group and the radical-left GUE/NGL would be ready to support him.

One of them also affirmed that some S&D MEPs were ready to back the liberal leader, rather than their own official candidate Pittella.

Verhofstadt's attempt to break the EPP-S&D grand coalition could be what it takes to win support from other groups, at a time when Schulz's cosy relationship with Juncker, the EPP EU commission chief, will evaporate.

"We have a political commission, it's time to have a political parliament," an Alde source told this website.

The longing for change among MEPs was acknowledged by an EPP top MEP.

"I wouldn't rule out Verhofstadt either," the MEP said in Brussels earlier this week. "His moment is now."

But some in the Alde think, despite his political clout, Verhofstadt's personality could block him from leading the 751-strong chamber with its nine groups across the political spectrum.

Verhofstadt is "too federalist and too provocative" to be elected, an MEP told EUobserver in Warsaw. "Many people like him, but many people hate him."

Low profile

The MEP pointed out that the group's leadership rushed to back him earlier this week after French MEP Sylvie Goulard announced she was running for president, and suggested that internal debate has been stifled ahead of the congress.

For now, Telicka said Verhofstadt "has a strong mandate from the group to negotiate all the mid-term package," not only the parliament's presidency.

He said that in negotiations with other group leaders Verhofstadt would try to change the way the parliament functions.

"If someone else is president, so be it," he said. "But it should be a strong head of parliament, who has the courage to address political issues and is more inclusive."

Verhofstadt has until 16 January, the day before MEPs vote to choose their new president, to gather more who like him than who hate him.

That's why the liberal leader, somehow unusually for him, kept a low profile on the issue in Warsaw.