While insisting he is running to head the commission, Juncker, 59, has said he would be honored to serve as president of the European Council, succeeding Belgian Herman van Rompuy as full-time chairman of EU summits, a key broker of compromises.
The other jobs in the mix include EU foreign policy chief, currently held by Britain’s Catherine Ashton, the Eurogroup chairman and the president of the European Parliament.
Other potential contenders include Danish Prime Minister Helle Thorning-Schmidt and former Italian prime minister Enrico Letta on the center-left, Lithuanian President Dalia Grybauskaite and the prime ministers of Finland and Ireland, Jyrki Katainen and Enda Kenny, on the center-right.
Each has drawbacks as well as advantages and none stands out as an overwhelming natural choice, but then nor did Barroso.
Thorning-Schmidt’s country is not in the eurozone and some may argue that Nordic Social Democrats already have one big job with the appointment last week of former Norwegian prime minister Jens Stoltenberg as the new secretary-general of NATO.
Italy already has a major European position, with Mario Draghi at the European Central Bank. That would appear to rule out Letta, 47, and his predecessor, Mario Monti, 71, who is still revered in Brussels.
Grybauskaite, 58, a former EU budget commissioner who shares with the late Margaret Thatcher the nickname “Iron Lady,” would tick the gender, east European and small-country boxes.
However, some might object that she was a member of the Soviet Communist Party. She also appears to have taken herself out of the EU race by standing for a second term as Lithuanian president in May.
Katainen, 42, is a highly regarded modernizing ex-finance minister who has held together an unwieldy left-right coalition, but his country’s hard line on bailouts in the eurozone crisis may make him unattractive to southern EU states.
Kenny, 62, is admired for his leadership during Ireland’s successful bailout program, but the former schoolteacher has no international experience or foreign languages.
Thorning-Schmidt, 47, gained overnight celebrity with a “selfie” picture taken with US President Barack Obama and Britain’s Cameron at a memorial ceremony for Nelson Mandela in South Africa. However, the economic reformer has struggled to keep her ruling coalition together and is not popular with voters.
A Brussels insider said she and Kenny also suffer among core EU countries from being perceived as “the British candidates.”
Additional reporting by Luke Baker and Andrius Sytas