No matter how many troops President Obama orders to Afghanistan, victory will also require a surge across the Pakistan border that the Taliban and al Qaeda—but not American GIs—cross easily. The President knows this, but he hasn't made Pakistan's help any easier to obtain by signalling his intention to draw down a mere year after his surge troops arrive in Afghanistan.

Pakistan has slowly expanded its cooperation this year as its public and military have awakened to the threat from their own Islamist...