Jens Stoltenberg must wonder if he will ever be free. The NATO secretary general has now been in post for nine years — longer than anyone except the Netherlands’ Joseph Luns (1971–84) — and was supposed to step down last autumn. However, after the Russian invasion of Ukraine, he was asked by member states to extend his term by a year, and this month the North Atlantic Council voted to keep him in post for another year.

Some European leaders had been reluctant to back a UK candidate

If Stoltenberg was initially asked to remain at the helm to provide continuity whilst the alliance dealt with Russia’s war of aggression, his second stint of extra time is more about problems in agreeing on his successor. An early candidate was the Danish prime minister, Mette Frederiksen. Some member states were keen for a woman to lead NATO for the first time, but she would have been the third Scandinavian in a row, and Denmark’s defence budget is meagre at 1.38 per cent of GDP. In June, after a meeting in Washington with President Joe Biden, Frederiksen said she was not interested in the role.

A much stronger candidate emerged in the spring in the shape of the UK defence secretary, Ben Wallace. Running the Ministry of Defence under three prime ministers has proved his diplomatic skills; additionally, he has been resolute in his support for Ukraine, has the credibility of a former army officer, and has demonstrated the communications skills to lead NATO through a challenging period. He went so far as to defy convention and admit he was interested: “that’s a job I’d like,” he told the media.

Other names have been mentioned. Kaja Kallas, the articulate and determined prime minister of Estonia, is very able but takes a hard line on Russia and has been nicknamed “Estonia’s Iron Lady”. The Canadian deputy prime minister Chrystia Freeland is Ukrainian by ancestry. She caused enough trouble as a young journalist that the KGB described her as “erudite, sociable, persistent, and inventive in achieving her goals”. Like Kallas, however, she might be too provocative a candidate.

Wallace seemed convincing on paper, but towards the end of June, interviewed by The Economist, he admitted, “It’s not going to happen”. President Emmanuel Macron of France and some other European leaders had been reluctant to back a UK candidate, given the country’s exit from the EU — a rather petty reason, as NATO fulfils a different function and has a wider geographical footprint. There was also opposition from the White House, however, which is more significant.

One rumour suggests that Biden is under pressure from his wife Dr Jill Biden to prioritise a female candidate. If Kallas was too hard-line, Frederiksen had ruled herself out, and Freeland was a red flag to the Russian bear, where might the president look? The extraordinary idea now in circulation is that, with Stoltenberg staying in place until autumn 2024, Biden favours Germany’s Ursula von der Leyen, whose term as president of the European Commission will come to an end next November. On paper, this is a masterstroke: von der Leyen was German defence minister for five years from 2013 to 2019; she has international experience heading the commission; she is fluent in German, French and English; she supported Germany adopting a more robust foreign policy; and she is a woman.

Biden must know that American public opinion is slowly becoming more isolationist

There are factors to offset this. Germany still does not spend anything like two per cent of its GDP on defence. Plans boldly unveiled at the beginning of the war in Ukraine have been watered down to a cautious optimism that the target might be achieved in 2025. This is not von der Leyen’s responsibility, but it is indicative.

More significant is the fact that she was a hopeless minister of defence. A year into her tenure, an external report found that all nine of the Bundeswehr’s major procurement projects were behind schedule, by between 30 months and 30 years. Fewer than half of the Luftwaffe’s combat aircraft were airworthy. To sort out the mess, she spent hundreds of millions of Euros on external consultants, but only a fraction of the spending was declared, and the contracting procedures were flimsy and opaque. It did not go unnoticed that von der Leyen had spent 14 years working for McKinsey.

As president of the commission, von der Leyen has also been enthusiastic about an EU military capability. She created a system for Bundeswehr units to act as “anchors” for brigades from smaller EU nations. This is a potentially huge duplication of NATO capabilities, at a time when NATO is acting as the framework not only for Western security but also for the coordination of assistance to Ukraine.

We are all familiar with the concept of failing upwards, as Biden seems to want von der Leyen to do. Hard as it is to imagine the president as a fiendish plotter — there have been more Machiavellian rocks — one wonders if there is something deeper at work. Biden may want a female secretary general, but would one who supports an European Army and is steeped in Brussels integrationism be good for him?

Biden must know that American public opinion is slowly becoming more isolationist. Support for NATO, whilst still maintaining a majority, is in gradual decline. After all, Donald Trump spent four years in the White House during which, he now boasts, he confirmed allies’ fears that “if we don’t pay, you won’t protect us from Russia”. Would von der Leyen as secretary general give America the option to scale back its European commitments, to fulfil its military commitments elsewhere, perhaps in the Pacific?

The US currently provides 16 per cent of NATO’s direct funding — which pays for central command functions as well as diplomatic and civilian capabilities — but its European Command comprises 70,000 active personnel costing $25 billion per annum. That is a hefty commitment for a theatre which, until last February, represented little direct threat to US interests.

For the UK, von der Leyen’s candidacy is a dismal prospect. Her decision-making is secretive, she has little time for the soft-power diplomacy of cocktail parties and dinners, and her mindset is fundamentally integrationist, accretive of power rather than collaborative. Heading NATO requires persuasion and consensus, rather than building up powers at the centre. That would grate on many member states, and she has not shown much ability to adapt.

Wallace’s CV and skills make him potentially the most effective secretary general since Javier Solana: he is respected by fellow defence ministers, has the credibility of having worn uniform and is deft enough to manage the NATO 2030 change agenda. He is resigned to being passed over, though. Who said these appointments were fair?