America's hard-earned lessons from Iraq As the Bush administration winds down and Americans feel real accomplishment on Iraq after years of tough slogging, here's a dozen lessons learned for our nation. 1) War is easy, but peace is hard. America's Leviathan force handles any conventional threat out there, so our enemies refuse to fight straight up. Instead, they sit out the war, waiting to bleed us -- asymmetrically -- in the peace. If we can't master postwar environments, we'll achieve no lasting victories in this long war against radical extremism. 2) We once understood nation building, but we've had to learn it all over again.