Under the Bretton Woods system, foreign governments could retrieve gold bullion they had sent to the United States during the war by exchanging dollars for gold at the relevant fixed exchange rate. But enabling every major country to exchange dollars for American-held gold only worked so long as the U.S. government was fiscally and monetarily responsible. By the late 1960s, it was neither. Someone needed to pay the steep bills for Lyndon Johnson’s “guns and butter” policies — the Vietnam War and the Great Society, respectively — so the Federal Reserve began printing currency to meet those obligations. Johnson’s successor, Richard Nixon, also pressured the Fed to flood the economy with money as a form of economic stimulus. From 1961 to 1971, the Fed nearly doubled the circulating supply of dollars. “In the first six months of 1971,” noted the late Nobel laureate Robert Mundell, “monetary expansion was more rapid than in any comparable period in a quarter century.” That year, foreign central banks and governments held $64 billion worth of claims on the $10 billion of gold still held by the United States.