For most of American history, that office conveyed authority, dignity, and some measure of majesty upon its occupant. The great presidents—Washington, Jefferson, Lincoln, the Roosevelts—came to be viewed not merely as capable executives but as figures of myth: They were heroic, selfless, noble, godlike. Time has a way of burnishing reputations. But as late as the middle of the last century, Americans were inclined to view even incumbent presidents with reverence. Faith in the presidency may have reached its apogee soon after the Second World War. The public generally trusted Harry Truman and Dwight Eisenhower to be honest and well intentioned and to put the interests of the nation above their own.

It is no coincidence that the last president to inspire such trust was also the last president elected before the Vietnam War began in earnest. Kennedy’s charisma, and his military bona fides, encouraged Americans to believe in their young president as he confronted a complicated and dangerous world. His promise, in his inaugural address, that the United States would “pay any price, bear any burden, meet any hardship, support any friend, oppose any foe, to assure the survival and the success of liberty” reinforced Americans’ vision of their country as a muscular force for good around the globe.