In Iraq and Afghanistan, the United States has relearned painful lessons on how to win the peace. Institutionalizing these lessons requires establishing a common national strategic concept for post-conflict operations. Post-conflict operations are among the most difficult to plan and execute, even under the best of circumstances. Expectations that post-conflict activities will be smooth, uncomplicated, frictionless, and nonviolent are unrealistic, as is the assumption that grievous policy errors or strategic misjudgments cause all difficulties. The Administration and Congress must adopt policies that ensure effective interagency operations and unity of effort. Successful post-conflict operations cannot be planned effectively in Foggy Bottom or the Pentagon. Planning and implementation must be done in theater, in concert with the military combatant commands.