We are in the midst of a Dwight Eisenhower revival. Today pundits often look to Eisenhower as a model of how a president can govern across party lines and protect American interests globally without resorting too quickly to the use of force. Yet this mix of nostalgia and frustration with the current polarized state of American politics may mislead us. Eisenhower’s presidency has much to teach us today about how a president might avert crises and showdowns at home or abroad. But he governed...