The Islamic State militant group has just taken the city of Palmyra in Syria, putting at risk its magnificent ruins and raising two questions: Why did the government and its military not fight harder to hold the town and its oil fields? And will the Islamist radicals now engage in an orgy of cultural destruction, as they have done in Iraq?

It will be a while, if ever, before we know the precise circumstances under which Palmyra was taken. But the cafe owner who cried "Treason! It's treason!" as soldiers and police fled has cause to be suspicious. Public relations is an integral part of war, and losing Palmyra may work for President Bashar Assad.

Something similar happened around Dubrovnik, the Adriatic jewel of Croatia, in 1991 during the Yugoslav war. The fight for Dubrovnik was a turning point in that conflict, not because the Croats poured resources into the city to defend it, but because they didn't — whether by choice or because they lacked the resources — until much later. The city's Croatian commander, Gen. Nojko Marinovic (who at the time put on a brave face in daily morning briefings to reporters such as myself), said afterward he had quickly realized "the city was practically defenseless."