Mr Donald Trump's first visit to Europe was awkward. Its aftermath has been explosive. Speaking at an election rally in Munich, shortly after the US President had returned to Washington, Dr Angela Merkel came close to announcing the death of the Western alliance.
The German Chancellor warned: "The times in which we can fully count on others are somewhat over, as I have experienced in the past few days. We Europeans must really take our destiny in our own hands. Of course we need to have friendly relations with the US and with the UK and with other neighbours, including Russia. But we must fight for our future on our own."
Dr Merkel's remarks swiftly made headlines. Mr Richard Haass, who as president of the Council on Foreign Relations is the doyen of the US foreign policy establishment, tweeted: "Merkel saying Europe cannot rely on others & needs to take matters into its own hands is a watershed - & what US has sought to avoid since WW2."
It is easy and appropriate to blame President Trump for this state of affairs. But despite her cautious phrasing, Dr Merkel has also behaved irresponsibly - making a statement that threatens to widen a dangerous rift in the Atlantic alliance into a permanent breach.
The case against Mr Trump is easiest to make. His performance in Europe was disastrous. In a speech to Nato, the US President failed to reaffirm Article 5, the alliance's mutual defence clause.
This was not an accidental oversight and sent a clear message that America's commitment to the defence of Europe can no longer be taken for granted. That, in turn, risks encouraging Russia to test Nato's defences.
At a G-7 summit, Mr Trump stood alone in his failure to endorse the Paris climate accord. And he was also widely quoted as calling Germany "bad, very bad" for the sin of selling too many cars in the US.
Faced with all this, and with Brexit Britain, Dr Merkel may feel that she is merely stating the obvious in suggesting that Germany can no longer count on its American and British allies. Nonetheless, her speech was a blunder for at least five reasons.
First, it is a mistake to allow four months of the Trump presidency to throw into doubt a transatlantic alliance that has kept the peace in Europe for 70 years. It may come to that. But it is also possible that Mr Trump is an aberration and will soon be out of office.
Second, the US President actually had a valid point to make about the failure of most European countries to meet Nato targets on military expenditure. Mr Trump's behaviour in Europe was crass. But his argument that it is unsustainable for the US to account for almost 75 per cent of Nato defence spending is correct - and was also made by Mr Robert Gates, defence secretary for president Barack Obama. Given that Germany has been free-riding on American military spending, it is a little cheeky to blame the United States for being an unreliable ally.
Third, by implying that the Western alliance is now coming apart, Dr Merkel has compounded the error that Mr Trump made when he failed to endorse Article 5.
Both events will have encouraged the Russian government in its hope of breaking up the Western alliance. That, in turn, makes Europe's security situation more dangerous.
Fourth, Dr Merkel was unwise and unfair to bracket Britain with Mr Trump's America. In the climate change discussions, Britain sided with the European Union - not the US. Similarly, the government of Mrs Theresa May has been at pains to stress Britain's commitment to Nato.
However, if Dr Merkel's government pursues the Brexit negotiations in the current confrontational spirit - demanding that Britain commits to vast upfront payments, before even discussing a trade deal - she risks creating a self-fulfilling prophecy and a lasting antagonism between Britain and the EU.
It is hard to see how Britain can be expected to see the same countries as adversaries in the Brexit negotiations and allies in the Nato context. So a really hard Brexit could indeed raise questions about Britain's commitment to Nato - particularly if the US is also pulling back from the Western alliance.
The final flaw in Dr Merkel's approach is that it displayed an uncharacteristic deafness to the echoes of history. One of the truly impressive things about modern Germany is that, more than any other country I can think of, it has thought hard about the lessons of history, and learnt them with thoroughness and humility. So it is baffling that a German leader could stand in a beer tent in Bavaria and announce a separation from Britain and the US while bracketing those two countries with Russia. The historical resonances should be chilling.
None of this is meant to suggest that Dr Merkel is on the same moral and political level as Mr Trump. The US President has repeatedly displayed contempt for core Western values - from freedom of the press and the prohibition on torture to the support of democracies around the world.
As a result, some have even proclaimed that the German Chancellor is now the true leader of the Western world. That title was bestowed prematurely. The sad reality is that Dr Merkel seems to have little interest in fighting to save the Western alliance.
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