Since the late 1950s, the rest of the world has come to use the dollar to an extent that justifies speaking of the dollar’s global domain. The rest of the world denominates much debt in U.S. dollars, extending U.S. monetary policy’s sway. In addition, in outstanding foreign exchange deals, the rest of the world has undertaken to pay still more in U.S. dollars: off-balance-sheet dollar debts buried in footnotes. Consistent with the scale of dollar debt, most of the world economic activity takes place in countries with currencies tied to or relatively stable against the dollar, forming a dollar zone much larger than the euro zone. Even though the dollar assets of the world (minus the United States) exceed dollar liabilities, corporate sector dollar debts seem to make dollar appreciation akin to a global tightening of credit. Since the 1960s, claims that the dollar’s global role suffers from instability and confers great benefits on the U.S. economy have attracted much support. However, evidence that demand for dollars from official reserve managers forces unsustainable U.S. current account or fiscal deficits is not strong. The so-called exorbitant privilege is small or shared. In 2008 and again in 2020, the Federal Reserve demonstrated a willingness and capacity to backstop the global domain of the dollar. Politics could constrain the Fed’s ability to backstop the growing share of the domain of the dollar accounted for by countries that are not on such friendly terms with the U.S.