Strategist Edward Luttwak once observed that strategy has a paradoxical logic. The best way forward may be the longest way round, offence can be the best defence, and a seemingly victorious course pursued indefinitely will lead to over-reach. This is produced by the limitations of human strength, the resistance and friction of conflict, and the sheer dynamism and chaos of war.This dynamic surfaces in the insurgency in Afghanistan and the terrorist-hunting campaign in Pakistan. Consider two headlines following Bin Laden's death. In Afghanistan, killing Bin Laden may not dis-spirit the...