A week before a crucial general election, the Prime Minister of Great Britain, Boris Johnson, finds himself today hosting probably one of the most important Nato summits in decades. The meeting of Nato leaders – in Watford of all places – could prove a turning point both for the future of the alliance and for European defence and security.

The core of the problem is continued doubts about the capricious President Donald Trump’s commitment to the alliance. Since branding it obsolete while campaigning for the presidency in 2016, he has gone on to question its core doctrine of mutual assistance and has fuelled fears that he may withdraw America from Nato entirely.

Trump is an unreliable ally. His transactional and isolationist foreign policy (“America First”) has unnerved allies. While he has not been wrong to cajole western allies into spending more on defence, he is seriously in error in treating alliances as transactions rather than a binding expression of common values.

Nato’s cohesion is further compounded by Turkey’s drift into the arms of Russia (see my column of November 20).

Into the vacuum created by western introspection and division, Russia, a regional power, has under President Putin interjected military might and ideological conviction. While its expansionism may in time prove to be an overstretch for a shaky economy, by then the damage will have been done.

In an intervention timed to explode just before the summit, President Emmanuel Macron has said that Nato is suffering from “brain death” and must rethink its role in a world where Europe can no longer rely on the United States for defence. He questioned specifically whether member states could still rely on the alliance’s central tenet (in Article 5 of the treaty), that an attack on one member state would be viewed as an attack on all.

When asked whether he believed in the effectiveness of Article 5, he said: “Nato only works if the guarantor of last resort functions as such… we should reassess the reality of what Nato is in the light of the commitment of the United States.” The question which Macron has raised goes to the heart of the alliance: if one of its 29 member states were attacked, would the other member countries help to defend it? He is right to say there should be clarity and it should be looked at again.

Following Trump’s abrupt announcement of the withdrawal of American troops from northeast Syria last month (a move since watered down if not entirely revoked), President Macron accused the US of showing signs of “turning its back on us”.

Macron has consistently urged Europe to “wake up” to the shifting power dynamics across the globe and to act in a more strategic manner, describing the continent as being on “the edge of a precipice”. 

All this has come at a time when the French president is seeking to seize the mantle as Europe’s leader. Macron said in an interview conducted in October – but published only recently in The Economist – that “if we don’t wake up… there’s a considerable risk that in the long run [Europe] will disappear geopolitically, or at least that we will no longer be in control of our destiny”. While he urged the resumption of a dialogue with Russia, behind his words lies the issue with which the European Union has grappled ever since Trump became President: European defence.

The hard reality for Europe is that Nato is as important now as it was at the height of the Cold War

Angela Merkel of Germany, whose authority is diminishing the closer her time to stand down as chancellor approaches, said she did not share the views behind Macron’s “drastic words”.

Although she has delivered similar warnings about Europe needing to take more responsibility for its defence inthe age of Trump, she views Macron’s questioning of Nato’s founding principle as alarmist. She said that “such sweeping judgments are unnecessary, even if we have problems and need to pull together.” She regards keeping Nato intact as more important than at any time since the Cold War: “the preservation of Nato is in our purest [national] interest.”

The secretary general of Nato, Jens Stoltenberg, took exception to Macron’s stance. He accused him of weakening the alliance and dividing Europe, insisting Nato was strong and that the US and Europe “work together more than we have done for decades”.

The problem lies with the erratic and unexpectedly pacific President Trump. The President, whose rhetoric is often belligerent with domestic opponents, has established a clear record after three years as one who is reluctant to deploy US forces in military confrontations, as his overtures to Kim Jong-Un of North Korea, his efforts to pull US forces from Syria last year, his reluctance to retaliate against Iran over the shooting down of a US drone all demonstrate.

When it comes to foreign policy, Trump is first and foremost a pragmatist. He is not driven by any particular ideology. But his desire to free America from foreign entanglements marks a worrying shift in US foreign policy. Many will detect a pattern. The President’s tepid response a month ago to Iranian attacks on Saudi oil installations has unsettled Saudi Arabia and Israel.

For similar reasons, eastern European countries are concerned that Trump’s treatment of Ukraine could embolden Russia. Meanwhile, the President is threatening to launch a trade war against the European Union.

The hard reality for Europe is that Nato is as important now as it was at the height of the Cold War as the West faces very diverse threats from Russia, China and Iran.

The global competition between great powers could easily lead to inadvertent miscalculation and escalate the prospect of war. Nato’s relevance is back to where it was during the Cold War. The organisation has always had its tensions, but remains resilient. European security does not need to be reinvented.

There are two crucial challenges that will drive this Nato meeting.

First, to convince Trump of Nato’s relevance as the bedrock of western security. Both the US and European governments have a responsibility to maintain an alliance that has preserved peace for 70 years. The summit’s decisions will affect the long-term viability of two multilateral bodies, Nato and the EU.  

Secondly, how best to reform by encouraging closer European cooperation on defence while retaining Europe’s umbilical cord to the Atlantic Alliance and ensuring European nations, including post-Brexit Britain, create a stronger European pillar of Nato.

These issues are vitally important to the EU, including Malta.