Even by his own bombastic standards, for Donald Trump to get up at a joint press conference and denounce his own intelligence agencies was quite something. This was no deft, nuanced, damning with faint praise, disdainful dismissal, either. It was the sort of overstated all-out attack he used to reserve for Hillary Clinton, who made another appearance on the international political stage, as an increasingly exasperated President Trump tried to distract attention from the allegations about his own presidential campaign.

As ever, he may be right about secretary Clinton’s missing 33,000 emails; but that does nothing to absolve him, and nothing to excuse the violence of his attacks on the FBI. Normally, an attack such as this in the presence of the US president by a Russian leader would spark a diplomatic incident.

This was the performance of a president more rattled by his own security forces than he is about those of the Russian federation. For Mr Trump what is going on is “a witch hunt”. “There is no collusion.” “Zero collusion”. The Mueller probe is, so the head of the executive branch of the US government declared, “a disaster for our country”. “It was a clean campaign.” The allegations are “ridiculous.” America’s commander-in-chief rained fire and fury down – on his own agencies and officers.

Trump in Helsinki: Putin meeting and protests Show all 16 1 /16 Trump in Helsinki: Putin meeting and protests Trump in Helsinki: Putin meeting and protests President Trump meets with Russian President Vladimir Putin in Helsinki Reuters Trump in Helsinki: Putin meeting and protests An advert from Finnish newspaper Helsingin Sanomat is on display in Helsinki Reuters Trump in Helsinki: Putin meeting and protests President Trump in a meeting with Finnish President Sauli Niinisto AFP/Getty Trump in Helsinki: Putin meeting and protests President Trump meets with Finnish President Sauli Niinisto in Helsinki EPA Trump in Helsinki: Putin meeting and protests President Trump talks with Finnish President Sauli Niinisto in Mantyniemi, the official residence of the Finnish President EPA Trump in Helsinki: Putin meeting and protests US, Finnish and Russian flags fly in front of the Presidential Palace in Helsinki EPA Trump in Helsinki: Putin meeting and protests A protester wears a mask featuring a portrait of Russian President Vladimir Putin during the so-called "Helsinki against Trump and Putin" demonstration on July 16, 2018, in the Finnish capital Helsinki. The US and Russian leaders opened an historic summit in Helsinki on Monday, with Donald Trump promising an "extraordinary relationship" and Vladimir Putin saying it was high time to thrash out disputes around the world. / AFP PHOTO / Jonathan NACKSTRANDJONATHAN NACKSTRAND/AFP/Getty Images JONATHAN NACKSTRAND AFP/Getty Trump in Helsinki: Putin meeting and protests Vladimir Putin gifts a football to President Trump at the press conference that followed their meeting AP Trump in Helsinki: Putin meeting and protests Trump supporters hold banners during a demonstration in Helsinki AFP/Getty Trump in Helsinki: Putin meeting and protests People protest for women's reproductive rights in Helsinki's Senate Square Reuters Trump in Helsinki: Putin meeting and protests A crowd watches the motorcade transporting President Trump through Helsinki AFP/Getty Trump in Helsinki: Putin meeting and protests Russian President Putin drives through Helsinki on his way to meet with President Trump EPA Trump in Helsinki: Putin meeting and protests A man in the audience of the joint press conference holds up a sign sign that reads "NUCLEAR WEAPON BAN TREATY". REUTERS Trump in Helsinki: Putin meeting and protests A man is removed from the joint press conference in Helsinki. Security removed the man after he pulled out a sign that read "NUCLEAR WEAPON BAN TREATY". REUTERS Trump in Helsinki: Putin meeting and protests President Trump and Russia's President Putin sit for a working lunch in Finland's Presidential Palace AFP/Getty Trump in Helsinki: Putin meeting and protests President Trump meets with Russian President Vladimir Putin in Helsinki Reuters

Needless to say, it’s no surprise that Mr Trump didn’t press the allegations against 12 Russian military intelligence GRU officers.

It is interesting how frequently the president chose to use the phrase “no collusion”, or variants of it. It suggests very much that there were contacts between the Russians broadly, and the Trump camp, broadly, but President Trump wishes to set a high bar for any possible concrete allegations made against him – specifically collusion, a harder test than some others.

It may well be that the Russians provided the Trump campaign with intelligence and leaks, directly or via Wikileaks, and they made use of them, but without close-range collusion. The Mueller inquiry will determine that. Mr Putin helpfully suggested only a court trial could do so.

If only that was the only depressing aspect of this mini-summit. At times Mr Trump sounded almost statesmanlike, preferring jaw jaw to war war. But there was little to suggest that America is yet securing a new relationship with the Russians by doing anything else than selling out.

Fresh from a major propaganda coup of his own, the Fifa World Cup finals, Vladimir Putin must feel well pleased that his protagonist has spent the past few days winding up his Nato allies generally, insulting Germany, describing the European Union as a “foe”, and humiliating Theresa May. Perhaps President Trump feels that his brand of fresh diplomacy is to confront his friends and allies; and to appease an expansionist and aggressive Russia that has proved itself willing to subvert democracy even in the United States itself. It is irrational.

No one wishes to return to the days of the Cold War. Yet Donald Trump and Vladimir Putin (more surprisingly) betrayed a deliberate ignorance of history when they said US-Russian relations have never been worse – successive postwar crises over Berlin, Hungary, Cuba, the Czech spring, Vietnam and Afghanistan were surely worse episodes, let alone the dispatch of American troops to take part in the Russian civil war a century ago.

Still, this was no history lesson. What it was, though, was a flawed attempt by Donald Trump to assert his prowess as a dealmaker and deliver on another campaign promise – to make peace with Russia. Having publicly invested so much political capital on the pledge, he risks having to fulfil at too high a price for the American national interest, and the interests of the west more broadly.

The worst fears were not realised. There was no sacrifice of Ukraine or Crimea in return for a Russian hand in taming Iran, but both men left that hanging in the air, for future trading.

There is something to be said for personal diplomacy and the “bold” diplomatic tradition that President Trump cited. When Richard Nixon, the great Cold War warrior, opened relations with Mao’s “Red China” in 1972, he changed the course of world history.