n the aftermath of World War II, the United States accepted the mantle of global

leadership and worked to build a new global order based on the principles of

nonaggression and open, nondiscriminatory trade. An early pillar of this new

order was the Marshall Plan for European reconstruction, which British historian

Norman Davies has called “an act of the most enlightened self-interest in history.”

1 America’s leaders didn’t regard this as charity. They recognized that a more

peaceful and more prosperous world would be in America’s self-interest.

American willingness to shoulder the burdens of world leadership survived a

costly stalemate in the Korean War and a still more costly defeat in Vietnam. It even

survived the end of the Cold War, the original impetus for America’s global activism.

But as a new century progressed, this support weakened, America’s influence

slowly diminished, and eventually even the desire to exert global leadership waned.

Over the past two decades, the United States experienced a dramatic drop-off in

international achievement. A generation of Americans have come of age in an era in

which foreign policy setbacks have been more frequent than advances.