Since the end of the Cold War, the United States has lacked a grand strategy to replace "containment of communism." In this vacuum, the Bush administration has used the "war on terrorism" as an excuse for unilateralism, preemption, and hegemony. This essay outlines a much broader set of large purposes--achieving security, expanding opportunity, and promoting democracy--to which America's economic, political, and military powers may be applied. America is at a crossroads between empire and republic. In this bold new approach, Hart refutes preemption and empire, and argues for the fourth power--the power of principle--and the restitution of a principled American republic.