HELSINKI (Reuters) - Bavarian Manfred Weber cleared a first hurdle on Thursday in his bid to succeed Jean-Claude Juncker as EU chief executive after elections to the European Parliament in May.

Manfred Weber of Germany celebrates with his supporters after the results of the EPP lead candidate voting at the session of the European People's Party (EPP) congress in Helsinki, Finland, November 8, 2018. Lehtikuva/Markku Ulander via REUTERS

The Parliament has called for national leaders to pick a European Commission president from among the lead candidates -- Spitzenkandidaten in German -- of parties contesting the ballot.

Weber is the early frontrunner because his center-right alliance is likely to remain the largest group in Parliament, although horse-trading amongst EU leaders may result in another Commission chief. Leaders must nominate the president, but then lawmakers must approve the appointment in confirmation hearings.

The following are candidates or possible Juncker successors:

CONSERVATIVE CANDIDATE

MANFRED WEBER - A member of the European Parliament for 14 years, the 46-year-old German has led the biggest group in the legislature since 2014. Despite relative youth and lack of the government experience typical of Commission presidents, he won mass support from his European People’s Party (EPP) on Thursday to be its official lead candidate -- including from German Chancellor Angela Merkel and all other EU leaders in the EPP.

Diplomats say, however, that even if the EPP remains the biggest party, Weber’s route to the top job faces obstacles. EU leaders could defy Parliament and nominate someone who did not run in the election. Even Merkel may be less than committed to him -- Berlin like other capitals also wants to secure other big posts, notably head of the European Central Bank when President Mario Draghi steps down next October.

SOCIALIST CANDIDATE

FRANS TIMMERMANS - Juncker’s Dutch deputy, 57, is a former foreign minister and passionate, multilingual advocate for the EU but his party’s national eclipse counts against him.

First Vice-President Timmermans, who has led the Commission’s bid to thwart what it sees as authoritarian governments in Poland and Hungary, promises to bring the EU closer to ordinary voters at a time when Britain’s pending exit is inspiring other nationalist movements to challenge European integration.

He took the Socialist mantle when his Slovak Commission colleague Maros Sefcovic dropped out of the contest. But poor polling for the center-left, which has also seen Timmermans’ own party excluded from the Dutch coalition, poses an obstacle.

OTHER POSSIBLE CANDIDATES

MICHEL BARNIER - The EU’s chief Brexit negotiator ruled himself out of the EPP race, but the conservative former Commissioner and French foreign minister has earned respect from leaders over his handling of negotiations with London. He lost out in 2014 to Juncker to be the EPP lead and, despite being relatively old at 67, Barnier may still be in with a chance, possibly backed by French President Emmanuel Macron, a centrist who has led leaders’ rejection of the Spitzenkandidat system.

MARGRETHE VESTAGER - As a woman, aged 50 and with a star profile in Brussels from attacking tax avoidance and monopoly powers among U.S. multinationals like Google and Apple as the EU competition commissioner, the Danish former economy minister is widely talked about as a liberal who could win support beyond her party -- even if Denmark’s ruling conservatives oppose her. Macron, for one, could prove to be a powerful backer.

FEDERICA MOGHERINI - The 45-year-old was catapulted into the high-ranked Commission post of EU foreign policy chief in 2014. She could benefit from efforts to promote female candidates and a better left-right balance in Brussels. But she may struggle to get necessary support from the new populist coalition in Rome. Failure to run in the election will not please Parliament.

DALIA GRYBAUSKAITE - A nine-year veteran of the EU summit table and with one of the highest profiles in Brussels of any leader from the ex-Communist east, the Lithuanian president could be an outside bet. At 62, she worked as a commissioner under Juncker’s predecessor. As well as answering calls for a woman to lead the institution her appointment would also be a first for the eastern states which have joined since 2004.

MARK RUTTE - Dutch prime minister for eight years, the 51-year-old may be tempted by a new job. He is solidly pro-EU but appeals to those who want its budgets and powers kept in check. Liberal credentials may gain him support from Macron, although Rutte may also be tempted by next year’s vacancy to take over as EU summit chair from European Council President Donald Tusk.

ANGELA MERKEL - A wild card, but a switch to Brussels from Berlin may be a tempting option for the 64-year-old after she announced last week that she would not seek re-election in 2021 and will hand over her party leadership next month. Her stature would be seen as a major boost for the Commission, though her appointment might unsettle those who see the EU becoming a vehicle for an ever more powerful Germany to run Europe.