Another outtake from the Project for a New American Century paper, pg. 42. Emphasis mine

American landpower remains the essential link in the chain that translates U.S. military supremacy into American geopolitical preeminence. Even as the means for delivering firepower on the battlefield shift – strike aircraft have realized all but the wildest dreams of air power enthusiasts, unmanned aerial vehicles promise to extend strike power in the near future, and the ability to conduct strikes from space appears on the not-too-distant horizon – the need for ground maneuvers to achieve decisive political results endures. Regimes are difficult to change based upon punishment alone. military preeminence.