THE GROWING COST OF DEFENSE that Adam Smith foresaw 236 years ago now poses a familiar challenge for American conservatives. The “guns versus butter” debate goes back at least to the Lyndon Johnson era. But then our economy was strong, and our enemy—the Soviet Union—was visible, personified by its odious leaders, and a clear threat. But now our economy is weak, made so by President Obama’s hyper-expansion of government and debt. It has apparently lost its ability to grow, and without growth there cannot be recovery or prosperity. President Obama’s military build-down has already imposed massive cuts on the Pentagon’s budget, resulting in a significant reduction in our current and future military capabilities. The fiscal realities—with which Congress refuses to deal—make more cuts inevitable.