After the Syrian Army recaptured the city of Palmyra from the Islamic State group at the end of last month, U.S. State Department spokesman John Kirby admitted that the liberation of the ancient city was a "good thing". But he could not resist adding: "We're also mindful, of course, that the best hope for Syria and the Syrian people is not an expansion of [President] Bashar Assad's ability to tyrannize the Syrian people."

This was entirely in line with the long-standing U.S. policy of seeking to destroy both Islamic State and the Syrian government (i.e. the Assad regime) at the same time. But that was never more than wishful thinking, especially as the United States was quite sensibly determined not to commit its own ground troops to the conflict.

If the Syrian Army actually had collapsed (as was looking quite likely before the Russians intervened to save it last September), nothing could have prevented Islamic State and the rival Islamist forces of the Nusra Front from taking the whole country. They might then have fought each other for control, but all of Syria would have ended up under extreme Islamist rule.