American-led global interventionism has been one of those defining constants of European politics for so long that only the very, very elderly can remember when it was not so.

Wars or bombings or invasions in Iraq, Libya, Afghanistan, Kosovo and Grenada have all generated the same arguments as Vietnam and even Korea. European governments and populations have backed some and not others. All with very familiar arguments about whether the US should be the world’s policeman.

But as Turkish tanks crush traditional American allies in Syria some of columnists are starting to wonder what the planet will be like without an armed US cop.

The Daily Telegraph

Back in the old world order, Fraser Nelson would be one of those who would be supporting US action to support Kurds.

But Donald Trump, he writes, is “fed up with America being the world’s policeman. He’s walking away from the role, and his allies will have to get used to it. For allies like Britain, this is all rather serious”.

As Mr Nelson says, isolationism is not just about the current albeit erratic occupant of the White House.

He writes: “This is not just Trumpian madness. Most of the 20-odd Democrats running for the presidential nomination offer their own versions of Trump’s arguments: that too much blood and money has been spent trying (and failing) to solve problems in the wider world.

“Polls show Americans have come to regard the George W Bush missions as a miserable failure.”

Mr Nelson thinks they have a point.

He adds: “The new Turkish drama at least offers us a glimpse of what the world looks like without America. Vladimir Putin, who is busy putting together an oil network in Syria and the Middle East, can now present himself as the dominant force in the region.”

Mr Nelson cites a recent study showing it would take the UK three months to pull together a brigade if Russia invaded Latvia. Nato needs America. But America, under its current leader, is all jaw-jaw, or tweet-tweet. And nobody fears its words He concludes: “Trump has become a president who speaks loudly while carrying a small stick. For America’s allies, it’s the worst possible combination.”

Financial Times

Like Mr Nelson, Philip Stephens thinks US isolationalism is here to stay.

“Mr Trump,” he writes, “has broken the rhythm of history. We expect threats to the established order to come from rising powers.

“The assault on the postwar Pax Americana, however, has been led by, well, America. When Europeans fret about another war breaking out they have usually been looking at Mr Trump’s Twitter account.”

Donald Trump, the analyst points out, does not have any “grand strategy”. He adds: “His worldview is shaped by a set of emotional impulses. Looking for a framework is like searching for symmetrical patterns in a bowl of spaghetti. This is the president, after all, who lionises North Korea’s Kim Jong Un, a dictator upon whom he once threatened to rain “fire and fury”.

For Mr Trump, reckons Mr Stephens, multilateralism - the lynchpin of such world prosperity and peace as we have - “is a globalist plot against the US.”

He writes: “Most Europeans will tell you that the world has had a Trump problem, not an American one. To the extent that this president’s behaviour has been uniquely capricious, they have a point. But the clock cannot be turned back to an era that was passing before Mr Trump reached the White House. “ Sure, he concedes, “the world should be safer without Mr Trump.” But, he reckons, the “protectionist tilt will harden” under whoever replaces Mr Trump.

The National

Scottish foreign reporting veteran David Pratt, writing in The Herald’s sister paper, reckons Mr Trump’s abandonment of the Kurds also asks hard questions of UK governments which arm Turkey.

He writes: “Turkey’s incursion into northern Syria threatens not only the future of the Kurds but also the basic stability of the entire country. It marks a watershed in the notion that the US can be trusted as a partner and will once again allow the barbarians of Daesh to breath and possibly even thrive.

“The UK right now needs to distance itself from Washington’s foreign policy madness and Ankara’s antipathy toward the Kurds.

“But that’s simply not going to happen, not least given this current shambles of a government.”