The NATO Summit in London takes place before the UK goes to the polls and as deep cleavages between Euro-Atlantic partners has been difficult to hide.

Prime Minister Boris Johnson and President Donald Trump were photographed during the summit but avoided a bilateral public meeting. One of the critical issues of the campaign has been speculation over US demands for a more open agri-food market and greater access to the British National Health Service.

President Trump has become the subject of numerous controversies during the two-day NATO summit. A 25-second clip aired by CBS on Wednesday featured Canadian prime minister Justin Trudeau, Boris Johnson, French President Emmanuel Macron, and Dutch Prime Minister Mark Rutte laughing about the US President’s behaviour. But this was not the most serious of the emerging cleavages between Euro-Atlantic Allies. On Wednesday evening, President Trump cancelled a press conference that was scheduled on Thursday to return to Washington.

In more substantive terms, the US successfully pushed on the agenda the recognition of China as a common security “challenge” if not altogether a “threat.” As noted by NATO Secretary Jens Stoltenberg, China has the second-biggest defence budget in the world and is increasingly making its presence visible in the Arctic. However, in the broader context of US punitive tariffs against China and Europe, allies do not see eye-to-eye when it comes to dealing with the second biggest economy in the world. The deep and evident divide comes to the fore when addressing the question of Huawei’s involvement in the development of 5G infrastructure.

Another divisive issue has been defence spending. President Trump continues to remind all his partners of the need to meet the Alliance’s 2% of GDP threshold agreed in 2014. Since 2016, NATO allies that meet the threshold have increased from five to eight. But there are 29 members states and Germany has vowed to comply within a decade.

The broader economic context also created a confrontation climate. On Tuesday US President Donald Trump and French President Emmanuel Macron had a confrontation in front of the media. As the US announced punitive tariffs on French goods – as a reaction to a digital tax introduced by France and Italy, and the UK – President Macron talked about the need to consolidate a “European pillar” within NATO.

And then there is Turkey.

The summit takes place following the Turkish incursion in Northern Syria against the Kurdish-led Syrian Democratic Forces (SDF), with whom both French and US troops fought shoulder-to-shoulder against ISIS.

“When I look at Turkey, they now are fighting against those who fought with us shoulder to shoulder against IS,” Macron said on Tuesday.

President Trump withdrew US troops allowing Turkey to invade and is standing by his decision. In the meantime, Turkey has doubled-down on its independent course of action, buying a Russian missile defence system (S-400) and negotiating the procurement of Russian jet fighters.

A more severe crisis within NATO was averted on Wednesday.

President Recep Tayyip Erdogan threatened to hold up a NATO defence plan for the Baltic states and Poland if allies did not designate the US-backed People’s Protection Units in Syria as a terror organisation. Secretary Stoltenberg announced that the threat was withdrawn.

While President Macron is the only one who dared call the Alliance “brain-dead” – a comment condemned by President Trump as “nasty” and “disrespectful” – it is clear that the gulf between Euro-Atlantic partners is widening.