U.S. Secretary of State Marco Rubio walking between the U.S. and Japanese flags.

Marco Rubio, the US secretary of state

ALEX BRANDON/REUTERS

There is an “unbreakable link” between the United States and Europe and the former will ­“always be a child” of the latter. These sentiments earned Marco Rubio, the US secretary of state, a standing ovation from European diplomats when he ­delivered them in a speech at the annual ­Munich Security Conference on Saturday.

In his tour d’horizon of transatlantic relations, Mr Rubio adopted a markedly more emollient tone than JD Vance, the US vice-president, who at this ­venue last year blamed Europeans rather than Russia for the Kremlin’s brutal war against Ukraine.

Hence the audience’s relief. Yet Mr Rubio did not jettison the Trump administration’s premise that the US and Europe are pursuing divergent philosophies rather than a common cause. He merely expressed it more politely. And this is a danger for the free world. Western European ­democracies can no longer count on US support. They must not resile from the causes of defending liberty against Russia’s imperial aggression, and of protecting their own way of life.

A close reading of Mr Rubio’s speech indicates a view that Europe is in civilisational decline, threatened by malign internal forces and waves of immigration. The Trump administration has condemned Europe for alleged over-regulation, encroachments on free speech and freeloading on US military power.

The critique is arguable but the inference from it dangerous. Democratic governments are fallible, to be sure. But the transatlantic alliance is not a transactional relationship in which favours are reciprocated and infractions punished. It is a shared endeavour for collective security. The Trump administration has appeared swifter to confront allies than contain autocratic adversaries. This is a huge shift in the dynamics of the international order and not for the good.

Mr Rubio at least did not hold European ­governments responsible for the war in Ukraine, but the Trump administration has consistently treated the Putin regime in Moscow as a ­legitimate interlocutor rather than the brutal ­aggressor it is. Mr Rubio conspicuously cancelled a meeting on Friday to discuss Ukraine with European allies, ostensibly because of a scheduling conflict. This did not give a reassuring message.

There is a long tradition of attempts by US presidents to broker peace deals, encompassing Theodore Roosevelt’s negotiation of the 1905 Treaty of Portsmouth, which ended the Russo-Japanese war, and Jimmy Carter’s efforts in the Camp David accords of 1978, establishing peace between Israel and Egypt.

The Ukraine war is not that type of conflict. It is a clash of right and wrong, in which the sole basis for lasting peace is for Ukraine to prevail. The Trump administration’s diplomacy has increased tensions by casting doubt on the West’s commitment, thereby eroding deterrence.

Countervailing voices in US debate are weighty. A statement issued last week by 16 senior military and diplomatic figures stressed that the Nato ­alliance is not an act of generosity on America’s part but rather “a strategic bargain” that ensures the US “remains the world’s most powerful and economically secure nation at a fraction of the cost of going it alone”. The Trump administration’s ­position is historically aberrant but a fact. Even when President Trump leaves office America’s commitment to Europe will still be open to question. Slapping tariffs on allies and threatening to annex their territory is a radical precedent. European governments may, for reasons of expediency and economy, seek to withdraw from commitments and hope for the best. That would be a dis­astrous mistake. They must maintain the means to defend themselves and swiftly achieve a minimum ­defence budget of 5 per cent of GDP annually.

It will be expensive, but the price of deterrence is lower than the costs of allowing aggressive autocracies to pursue their ends unhindered.