Europe's likely next president may need far-right votes to win. Some see that as a 'catastrophic sign'

Ursula von der Leyen is favorite to succeed Jean-Claude Juncker (right) as European Commission President.

(CNN)Germany's Ursula von der Leyen is on the verge of succeeding Jean-Claude Juncker to become the European Commission's first female president on Tuesday -- if leaders of the 28 EU member states have their way.

A long-time ally to German Chancellor Angela Merkel, and the only minister to have served in Merkel's cabinet since she came to power back in 2005, von der Leyen's nomination to replace Juncker was unexpected since she wasn't even a candidate.
"She didn't campaign, she never came out, she didn't take part in any debate," explains Anna Nadibaidze from the policy think tank, Open Europe.
    Von der Leyen has long been an ally of German Chancellor Angela Merkel and her longest-serving minister.
    European leaders nominated the German defense minister to lead the Commission after they failed to agree on any of the "Spitzenkandidat" nominees -- who are put forward by European political parties ahead of the EU elections. Von der Leyen beat the original frontrunner for the role -- Dutch socialist Frans Timmermans.
    And while her nomination was supported by a majority of EU leaders, it's unclear if she'll receive the same support when 751 Members of the European Parliament vote to approve the appointment on Tuesday.

    Nomination seen as a 'backroom' deal

    Von der Leyen, 60, may not receive the majority she requires from parliament, due to critics branding her nomination a "backroom" deal.
    "Her nomination is mostly seen as a French-German deal that was done behind closed doors and some people call it a stitch-up," Nadibaidze told CNN.
    "That's the danger -- that she might not get accepted specifically because of the process."
    Domestically, Nadibaidze says, von der Leyen has faced a lot of criticism, particularly from Merkel's coalition partners -- the Social Democrats (SPD), who are upset that EU leaders ignored the top candidates after days of horse-trading.
    "They think she's one of the weakest ministers (and) that she couldn't command the army," Nadibaidze explains. "There was also an article in the German press saying that how the German army is happy to get rid of her."