Ursula von der Leyen faced the European Parliament on Tuesday ahead of a knife-edge secret vote to confirm her in Brussels’ top job.

The 60-year-old conservative will replace Jean-Claude Juncker as president of the European Commission if she secures a majority in the Strasbourg assembly.

If she fails – and the ballot could be close – then Europe faces a summer of institutional infighting between parliament and the 28 EU leaders.

And if her victory is close or is secured only thanks to eurosceptic members, her position will be weakened even before she takes over as the commission’s first female leader in November.

She has had barely two weeks to make her case since the leaders declared her the nominee after a tense three-day summit, casting aside candidates backed by parliament.

But von der Leyen has responded with a series of written promises to the main centre-right EPP, socialist S&D and liberal Renew Europe blocs that she hopes will get her the necessary 374 votes.

And on Tuesday, she was broadly well received by sceptical lawmakers when she tried to reassure them of her environmental credentials and that she would build an inclusive five-year programme.

“I will put forward a green deal for Europe in my first 100 days in office. I will put forward the first ever European climate law which will set the 2050 target in law,” she said.

Her promise received applause, but Green leaders said it still lacked specifics and said they would not back her, leaving her parliamentary arithmetic much where it was.

A small ‘yes’

The nominee announced on Monday that she would step down from Angela Merkel’s German government this week whatever happens in the vote, underlining her European ambitions.

The three mainstream groups are expected to back her, but the Greens and the far-left will not, and the vote is a secret ballot that could contain surprises.

“It will be a small ‘yes’,” one well-placed European source predicted. “She’ll be elected with fewer votes than Juncker was five years ago.”

The former Luxembourg premier received 422 endorsements, and anything less than 400 would be seen as disappointing for the German veteran minister and mother-of-seven.

Another senior official said that if von der Leyen failed, outgoing Belgian premier Charles Michel would still become head of the European Council of EU leaders.

IMF director Christine Lagarde’s appointment to the European Central Bank would also remain on course, but the vacancy at the European Commission would be complicated to fill.

“Any new candidate for the European Commission presidency would have to come from the EPP family and could not be French. It would be a tricky situation, with gender balance back hanging in the balance,” he said.

The new head of the European Commission is due to take power on November 1, immediately after the latest deadline for Britain’s departure from the bloc.

He or she will have to manage the Brexit aftermath, Italy shirking its debt targets and efforts by Poland and Hungary to flout the EU-mandated rules of liberal democracy.

For that, the commission president will need a reliable majority in Strasbourg, but this year’s elections threw up a more fragmented EU parliament than ever.

At the same time, MEPs are frustrated by the way von der Leyen’s candidacy was foisted on them.

Under the EU Treaty, the head of the commission is nominated by member state leaders.

But many in parliament and in the Brussels EU institutions wanted the 28 heads of government to choose one of the parliamentary groups’ lead candidates.

Instead, they cast aside those names and chose to call on von der Leyen.

The biggest single group, Merkel’s conservative European People’s Party (EPP), will back her, despite seeing their parliamentary leader Manfred Weber cast aside.

But the centre-right’s 182 votes will not be enough by themselves, and many socialists and liberals are unconvinced.

Liberal parliamentary leader Dacian Ciolos nevertheless promised his support: “Our group is ready to back you insofar as you assert your independence.”

And for the socialists, Iratxe Garcia Perez, said: “We do not want an institutional crisis.”

“But we need guarantees that Europe will be able to lay the foundations for a sustainable future for all Europeans and for our common project,” she said.