AP Photo

As America begins to pull back its troops from Afghanistan, there's one consequence that gets little notice but is likely to have lasting impact: Pakistan is losing the best chance in its history to gain political control over all of its territory -- including the warlike tribal areas along the frontier.

Pakistan has squandered the opportunity presented by having a large U.S.-led army just over the border in Afghanistan. Rather than work with the U.S. to stabilize a lawless sanctuary full of warlords and terrorists, the Pakistanis decided to play games with these outlaw groups. As a result, Pakistan and its neighbors will be less secure, probably for decades.

This is a catastrophic mistake for Pakistan. Instead of drawing the tribal areas into a nation that finally, for...