Echoing the fears of European governments, FBI Director James B Comey announced last week that Americans fighting in Syria are being given “costly, round-the-clock surveillance” because of the threat they will pose to civilians after returning home.

As with the jihadis returning to Britain and Europe, they could prove bad news for America’s Jewish community.

Last month, an Israel official said that his government was working closely with its allies to keep track of the thousands of Westerners fighting in Syria. Battle-hardened and fired up by the antisemitism that is a bedrock of the Syrian opposition’s ideology, they could, he added, single out Jewish targets for terrorist attacks.

As Mr Comey was speaking, a leading British military historian and government adviser, Sir Hew Strachan, was castigating Downing Street and the White House for their lack of military strategy in Syria and the wider Middle East.

Both governments, he was reported as saying, spectacularly bungled the Iraq and Afghanistan invasions and lack any understanding of the geopolitical consequences of the Syrian upheaval.

Sir Hew’s assessment is devastating because, as Chief of the Defence Staff’s Strategic Advisory Panel, he speaks from the heart of the British military establishment.

But if truth be told, he tells us little that sober observers of the region, appalled by how one military misadventure after another has caused misery and emboldened radical Islamist groups, haven’t been arguing for years.

Syrian jihadis, backed by the West and driven by their crazed lust for money, power and bloodshed, are turning on each other with a vengeance as well on their Western sponsors.

In an embarrassing u-turn, Britain and the US were forced this week to threaten the withdrawal of support for Syria’s opposition if it fails to join imminent peace talks.

Meanwhile, Syria’s deputy foreign minister said in an interview with the BBC this week that Western intelligence agencies have visited Damascus for talks on combating radical Islamist groups.

The BBC’s chief international correspondent, Lyse Doucet, said that informed sources had confirmed meetings between Western and Syrian intelligence officials.

Another report in the Wall Street Journal said that a retired official from MI6 had visited Damascus last summer, and that the French, German and Spanish intelligence agencies followed suit in November.

Iraq has descended into such jihadi-led chaos that some neoconservative American commentators — as ever, entirely missing the point — are now calling for a repeat invasion.

Libya’s economy is devastated, its streets still controlled by Islamist militias funded and trained by Nato. Meanwhile, the Taliban, whose ousting was the stated reason for the US-led invasion of Afghanistan, have emerged as political victors in that country.

Al Qaeda and its affiliates now control “more than 400 miles across the heart of the Middle East”, according to CNN’s terrorism expert Peter Bergen.

Now is surely the time for a radical rethink of our central policy of self-defeating military adventurism and turning a blind eye to diplomacy until the last minute.

One hopes it will not take a Syrian-led terrorist attack on our own shores to bring home the urgency of such a reassessment.

John R Bradley’s latest book is ‘After the Arab Spring: How Islamists Hijacked the Middle East Revolts’