The Federal Reserve is among the most powerful organs of government. It is tasked primarily with maintaining the growth of monetary and credit aggregates consistent with long-run maximum employment and price stability. This mandate is widely known and the subject of extensive public debate. But another mandate lies within the statute that is largely overlooked—to serve as fiscal agent of the United States. This distinct responsibility is older, and also important. This Article offers a comprehensive assessment of where the Fed’s two mandates overlap and occasionally sharply conflict: in the market for U.S. government debt. First, it identifies the legal and historical bases for the Fed’s role in facilitating “orderly markets” in government debt. Second, it clarifies what we call the “two mandates” problem: the Fed’s role as agent of the Treasury can compromise its ability to formulate independent monetary policy. Third, it reconstructs how the Fed outsourced the maintenance of orderly markets to the private sector to resolve the two mandates problem—an arrangement that was so successful that the Fed’s direct role slipped from view. Fourth, it explains how the outsourcing framework broke down after the 2008 financial crisis and why, in 2020, the Fed engaged in massive “market functioning” purchases. It concludes with an initial assessment of how the Fed might better fulfill its two mandates and avoid fiscal and policy dominance by the Treasury.