MARAUDING NATION

In Trumps second term, the U.S. could become a global bully.

- DAVID FRUM

In his first major address as president, Harry Truman urged Americans to use their enormous power "to serve and not to dominate."

The date was April 16, 1945. Adolf Hitler was still alive in his bunker in Berlin. Americans were readying themselves for a bloody invasion of the Japanese home islands. The atomic bomb remained a secret.

Yet Truman's thoughts were already shifting to the postwar future. "We must now learn to live with other nations for our mutual good. We must learn to trade more with other nations so that there may be, for our mutual advantage, increased production, increased employment, and better standards of living throughout the world." Truman's vision inspired American world leadership for the better part of a century.

From the Marshall Plan of the 1940s to the Trans-Pacific Partnership of the 2010s, Americans sought to achieve security and prosperity for themselves by sharing security and prosperity with likeminded others. The United States became the center of a network of international cooperation not only on trade and defense, but on environmental concerns, law enforcement, financial regulation, food and drug safety, and countless other issues.

By enriching and empowering fellow democracies, Americans enriched and empowered themselves too. The United States has led and sustained a liberal world order in part because Americans are a generous people and even more so because the liberal world order is a great deal for Americans.

Open international trade is nearly always mutually beneficial. Yet there is more to the case than economics. Trade, mutual-protection pacts, and cooperation against corruption and terrorism also make democracies more secure against authoritarian adversaries. Other great powersChina, India, Russia-face suspicious and even hostile coalitions of powerful enemies. The United States is backed by powerful friends.