Spend more on defense, shoulder more risk, accept more inconvenience, spurn Soviet and Russian natural gas, catch Kremlin spies, push back against communist-led trade unions, send European armed forces to fight in U.S. wars—the list was long. Europe’s contribution was never enough. Indeed, discontent about burden-sharing precedes the founding of NATO. At a 1949 Senate hearing on U.S. accession to the alliance, Secretary of State Dean Acheson was asked if this would mean “substantial numbers of troops over there.” He responded: “The answer to that question, senator, is a clear and absolute no!” The assumption at the bloc’s founding was that U.S. support was a bridge to European self-reliance.

The United States has long had a clear message to its European allies: Do more!

Spend more on defense, shoulder more risk, accept more inconvenience, spurn Soviet and Russian natural gas, catch Kremlin spies, push back against communist-led trade unions, send European armed forces to fight in U.S. wars—the list was long. Europe’s contribution was never enough. Indeed, discontent about burden-sharing precedes the founding of NATO. At a 1949 Senate hearing on U.S. accession to the alliance, Secretary of State Dean Acheson was asked if this would mean “substantial numbers of troops over there.” He responded: “The answer to that question, senator, is a clear and absolute no!” The assumption at the bloc’s founding was that U.S. support was a bridge to European self-reliance.

Ten years later, President Dwight D. Eisenhower complained that self-reliance wasn’t happening. “Our forces were put there on a stop-gap emergency basis,” he said, according to a 1959 memo. “The Europeans now attempt to consider this deployment as a permanent and definite commitment.” He complained that allies were trying to make the United States