In conflicts in places like Afghanistan and Iraq, political considerations must be taken into account, not just by civilian leaders and theater commanders, but also by lieutenants and sergeants.
If they fail to "change policy in response to military reality," the result is "like driving a car through the rear-view mirror rather than looking at the road ahead: It swerves all over the place and may crash."
This is hard for liberal democracies to do, he admits. But something like it has been done by U.S. and coalition troops, under General H. R. McMaster in Tal Afar, Iraq, in 2004-06 and General David Petraeus's in Anbar and elsewhere in 2007-08.
It is critical, Simpson argues, for the troops to live with the locals, getting to know them personally and gaining their trust. It is critical also to have a convincing "strategic narrative" that is flexible enough to appeal to different publics -- to soldiers, to locals, to neighboring countries and to elites and voters back home.
His major historical example, the 1962-66 British-Indonesian conflict in Borneo, is not entirely reassuring. There in response to Indonesian guerrilla and regular army attacks across the colonial border, British Commonwealth troops seasoned in jungle warfare in Malaya and Burma retaliated with cross-border attacks.
But this occurred largely out of view of the press and the public. Neither government, for reasons of its own, declared war nor acknowledged that a conflict was going on.
The recent raids in Libya and Somalia and drone strikes in Yemen and elsewhere suggest that the U.S., even after leaving Iraq and preparing to leave Afghanistan, is engaged in more conflicts than headlines indicate.
Some will take Simpson's book as an argument to avoid such conflicts altogether.
Others, who believe that the U.S. must act to eliminate terrorist havens, should take it as a warning that Simpson's wars, like Clausewitz's, are devilishly difficult.