As a former British ambassador to the US, I can tell you the G20 will achieve nothing this year – except making things worse

This is lowest common denominator diplomacy – and Trump could be about to cause serious problems with Putin and Xi Jinping

Anti-capitalism activists protest in Hamburg, where leaders of the world’s top economies will gather for a G20 summit (AFP/Getty)

On Friday and Saturday this week we shall witness in Hamburg a meeting of one of the world’s largest and most ineffectual international organisations. It is the G20, a gathering of the heads of the world’s 19 leading economies plus the European Union.

As usual, heads of several other countries and international organisations have been invited to attend as well, 37 in all. It means that if each participant makes a modest opening statement of, say, five minutes, three hours will have passed before any meaningful debate takes place.

But meaningful debate is, of course, not the point. On past form the meeting will produce a solemn and lengthy communiqué, probably entitled the Declaration of Hamburg, plus an action plan or two. These will have been pre-cooked by G20 officials under the stewardship of the Germans, whose turn it is to chair this annual diplomatic jamboree.

The documents will enshrine lofty aspirations on things like global trade and climate change. All the heads of delegation have to do is to sign on the dotted line. It is lowest common denominator diplomacy, papering over the conflicting national interests of participants.

The G20 sprang from the financial crisis of 2008, with an ambition to create global cooperation on a scale that would preclude future crises of this kind. But you would be hard pressed to say how any of these meetings have made a practical difference.

Even by the low expectations of the last nine years, the Hamburg meeting may disappoint. It may actually damage international relations, already fraught enough. The reasons are both structural and contingent.

The meeting takes place with a large hole where the US used to be. America has since the Second World War anchored the international system through bodies like the G20. It has been able most of the time to make its values and interests benchmarks for international cooperation. But with the irruption of Donald Trump, the US itself has become untethered, its external policies confused and unpredictable, such that the American President can no longer lay claim to leadership of the western or any world.

International relations, like nature, abhor a vacuum. But though there are many pretenders – Xi, Putin, Merkel, Modi, to name but four – none is of a stature to fill the role once played by the US.

The fate of these grand conferences is to be hijacked by a crisis and for the spotlight to fall on the many bilateral meetings which take place outside the conference chamber. Hamburg is no exception. Once again, Trump is at the epicentre. The crisis du jour is North Korea’s launch earlier this week of an intercontinental ballistic missile, a direct threat to the US.

In a rational world, Trump would sit down with Presidents Xi and Putin, the leaders of the two countries with the closest ties to Pyongyang, and hammer out a common strategy for dealing with Kim Jong-un. But Trump has already made things more difficult by blaming China for failing to control North Korea and putting public pressure on Beijing to stop trading with Pyongyang. Nor has it helped to accuse Russia of provoking instability.

Trump will have separate meetings with Xi and Putin. The scope for either meeting making relations worse is considerable. This is Trump’s first encounter with Putin. The press has decided that it will provide the headline of Hamburg.

The meeting is vitiated by investigations back in the US into Trump’s allegedly corrupt links with Russia. It is hard to see how he can have a cordial meeting with Putin without arousing suspicion back home, as happened when he met the Russian foreign minister in the White House last May. It looks politically impossible for Trump to give Putin comfort on his top priority, the lifting of economic sanctions.

More fundamentally, Trump has to decide whether Putin and Xi are partners or adversaries. Blowing hot and cold, as he has done with both, is no basis for a relationship.

The same might be said for America’s longstanding partners in Europe. Will he want to mend the fractious relationship with Merkel or send it further into the deep freeze? As things stand, Trump will find himself locking horns with all other G20 members on big-ticket issues like free trade and climate change.

As tear gas wafts over Hamburg, with thousands of anti-Trump demonstrators in the streets, I wonder if President Macron will come to regret his invitation to Trump to visit France on Bastille Day.

Sir Christopher Meyer is a former British Ambassador to the US