"This means quite a lot," Kallas, a former vice-president of the European Commission, told ERR on Monday. "For example, that there would be enough leadership positions in European Parliament committees for them, as well as possibly in EU leadership positions that change in summer and autumn."

Kallas highlighted that once the new European Parliament is convened in early July, a new president of the European Parliament will be elected, as will a new president of the European Commission, a new president of the European Council, a new High Representative of the European Union for Foreign Affairs and Security Policy, and a new head of the Eurogroup.

"Likewise currently very influential in the current makeup of the European Commission is the position of First Vice-President, and there has been talk of the possible establishment of a separate EU defense policy leader position," he added.

According to the Reform honorary chair, various election result predictions are projecting losses for what are currently the largest groups — the center-right European People's Party (EPP) and the Socialists & Democrats (S&D) — while euroskeptics, liberals and greens in particular are likely to gain seats. As euroskeptics may not necessarily join forces in a single group, however, liberals may see an extra boost in power in the next European Parliament.

The ALDE is typically third in size in the European Parliament, following the EPP and S&D, although currently just outranking it in the outgoing European Parliament is the European Conservatives and Reformists (ECR) group, which was established under the leadership of British Conservatives and opposes EU federalism.

ALDE regroup would follow elections

ALDE leader Guy Verhofstadt announced on Friday that following the May 26 European Parliament elections, the ALDE may disband and form a new centrist political group in cooperation with Macron's LaREM.

"Verhofstadt's tactic has always been to grow his group," Kallas said, adding that he has helped block the acceptance of one or another party into the ALDE in the past in order to prevent the weakening of its unity. "But the conservatives' group [EPP] has always been more homogeneous than the ALDE."

Kallas, who was elected second vice-president of the XIV Riigikogu last month, served as vice-president of the European Commission from 2004 to 2014. In November 2015, he ran for president of the ALDE, but was not elected.

The Netherlands' Hans van Baalen has served as president of the ALDE since 2015.

The ALDE also has groups of its own in the Parliamentary Assembly of the Council of  Europe (PACE), the NATO Parliamentary Assembly (NATO PA), and the European Committee of the Regions (CoR).