Donald Trump is undoubtedly the world’s biggest newsmaker. Even when he is alone in a room he airs grievances, settles scores and makes news through Twitter. When he is with other people, for example at the London anniversary summit celebrating 70 years of Nato for being what they call the "world’s most successful military alliance”, Mr Trump makes news in other ways too.
He was told by his aides that, with the British general election a few days away, he should not get involved in the politics of that country, and his first news conference was supposed to last just five minutes. The hope was that he would say something nice to bring a divided alliance of 29 member states together in celebration.
But Mr Trump’s news conference lasted almost 10 times as long – nearly 50 minutes – and he didn’t stick to the script. He praised Boris Johnson, the British prime minister, to the irritation of Mr Johnson’s election opponents. He called Justin Trudeau, Canada’s prime minister, “two faced” and characterised Emmanuel Macron, the French president, as “nasty” for saying Nato was “brain dead".
And that’s why I love summits, whether Nato or the European Union or the G7 or even when leaders get together at the General Assembly of the United Nations. Summits do not always make deals, but they almost always make news.
EU summits that I attended were at their best when diplomats nicknamed them “three shirters". The big ones (say, when Margaret Thatcher, the former British prime minister, had a spat with a French president – Francois Mitterrand or Jacques Chirac) would become so arduous that everyone needed a third change of clothing for the all-night sessions. But those arguments were intended to solve problems rather than create them. The leaders would debate from positions of mutual respect, leaving with a greater understanding of the problem even if still lacking a way to fix it.
The same was true of “Superpower Summits". From Ronald Reagan with Mikhail Gorbachev to Mr Trump with Vladimir Putin, a US president sitting down with a Russian leader at least demonstrates, in the famous phrase of Winston Churchill, that “jaw-jaw” was better than “war-war".
But a more sceptical view of summits is that they operate like a kind of leaders' trade union. World leaders get together to show their home audiences that they are important in a glorified photo-opportunity. It is certainly true – as the London Nato summit demonstrated – that Mr Johnson, Mr Trump, Mr Macron and Recep Tayyip Erdogan, the Turkish president, were all in their various ways keen to play to their home crowds. Mr Erdogan, for example, secured some language in the final Nato communique that could be interpreted as backing his stance against those Kurds he defines as terrorists, even if real divisions remain unresolved.
However, summits fail when the theatrical elements overwhelm any good they may achieve. The 2017 Nato summit is probably remembered – if at all – because Mr Trump pushed aside Dusko Markovic, the prime minister of Montenegro, in order to strut to the front of a photocall. The 2019 London summit will be remembered because Mr Trudeau, Mr Macron and Mr Johnson appeared to joke about what Mr Trudeau described as Mr Trump’s jaw-dropping news conference, and Mr Trump was clearly very angry. And that is where summits fail. The key to success is for all the real work to be done in advance, and for leaders to meet not to negotiate but simply to put a seal on an agreement worked out days, even months, in advance.
The British nickname for the clever civil servants who do all that work in the background is “sherpas", from the Nepali sherpas who guide climbers to a mountain summit. Mrs Thatcher had extremely talented sherpas. The same is true of Angela Merkel, the German chancellor, Mr Macron and Mr Trump.
The Nato summit, though, had three inescapable problems.
The first is that the 29 members of an alliance formed in 1949 at the beginning of the Cold War can no longer agree what the purpose of it is, nor precisely what “enemy” they are protecting each other against. Russia? China? Terrorism? Second, Britain, the summit hosts, has in the past seen itself as a bridge between the US and Europe. But a country preoccupied by Brexit and a few days from an election is not in a good place to engage in complex diplomacy on other matters. The third problem is the worst of all: the US is an indispensable ally and the indispensable leader of Nato but Mr Trump’s "America First" instincts are suspected by his Nato partners of being fundamentally isolationist, in the tradition of “Fortress America” avoiding all “foreign entanglements".
However talented American sherpas are at leading him to the summit, Mr Trump sets his own course and sometimes decides to climb another mountain entirely. His style in summits with North Korea, China, Brazil and Russia is very personal. He has a clear hostility to multilateral agreements. His administration has pulled out of two major agreements that took years of backroom negotiations and summitry – the Paris Agreement on climate change and the Iran nuclear agreement.
Summits involve arguments but they also depend on the willingness of leaders to negotiate in good faith, to understand the political dilemmas other leaders face, and to compromise. A summit can never work as a zero-sum game of "I win, therefore you lose". Moreover, while it helps if leaders actually like each other, it is not necessary. Diplomats on both sides told me John Major, the former British prime minister, and Bill Clinton, the former US president – two affable men – had absolutely no personal chemistry but did work successfully together. Mr Trump claimed great personal chemistry with North Korea’s Kim Jong-un but unfortunately their summits have so far come to nothing substantive.
Goodwill and backslapping are never a substitute for hard work. But at least summits always leave someone happy – mostly the journalists who know that they will be able to report on some big news from the world’s biggest newsmakers.
Gavin Esler is a journalist, author and presenter