Note: This is part of a strategic dialogue on Afghanistan. You can read Erik Leaver’s piece here.

A major U.S. effort in Afghanistan makes no sense in its own right: a faraway country with very limited resources and a history of hostility to invaders. But Afghanistan was intimately involved with the World Trade Center attack — a major psychological blow to the American people, and that has given Afghanistan a major psychological tie in U.S. minds. The present focus on Afghanistan, as articulated by President Barack Obama, "has a clear mission and defined goals — to disrupt, dismantle and defeat al-Qaeda and its extremist allies."