Two great sieges are getting under way in the Middle East, one in Mosul, Iraq, and the other in Aleppo, Syria. They have a great deal in common, including the fact that the attackers depend heavily on foreign air power, but they are treated by most international media as though they were completely different events. How similar they are will become clearer with the passage of time.

Sieges of cities, once a major part of warfare, grew rare in the course of the 20th century, mainly because of the rise of air power. You didn't need to besiege cities any more because you could just smash them to smithereens from the air: Guernica, Dresden, Hiroshima. But that's not so easy in the era of instant global media coverage.

Seventy years without a really major war have allowed us to develop a major dislike for killing civilians from the air. Nobody on either side would have been the least bit reluctant to blast Aleppo or Mosul into oblivion in 1945 if it served their strategic purposes, but moral tastes have changed.