Decades ago, Secretary of Defense Robert McNamara asked the simple question: how much is enough? The answer, of course, is not a number but rather another more difficult question: enough for what? As the U.S. military embarks on a new operation in the Middle East and as members of Congress return to their home districts to campaign, these questions remain unresolved. Should the military be resourced to fight terrorist groups like ISIL, counter Russian moves in Eastern Europe, balance China’s rising power and influence in the Asia Pacific region, fight Ebola in Africa, or some combination of these?