20 Years of War – A Costs of War Research Series, Watson Institute of Public and International Affairs, Brown University: “The United States has appropriated and is obligated to spend an estimated $6.4 Trillion through Fiscal Year 2020 in budgetary costs related to and caused by the post-9/11 wars—an estimated $5.4 Trillion in appropriations in current dollars and an additional minimum of $1 Trillion for US obligations to care for the veterans of these wars through the next several decades. The mission of the post-9/11 wars, as originally defined, was to defend the United States against future terrorist threats from al Qaeda and affiliated organizations. Since 2001, the wars have expanded from the fighting in Afghanistan, to wars and smaller operations elsewhere, in more than 80 countries —becoming a truly “global war on terror.” Further, the Department of Homeland Security was created in part to coordinate the defense of the homeland against terrorist attacks. These wars, and the domestic counter terror mobilization,have entailed significant expenses, paid for by deficit spending. Thus, even if the United States withdraws completely from the major war zones by the end of FY2020 and halts its other Global War on Terror operations, in the Philippines and Africa for example, the total budgetary burden of the post-9/11 wars will continue to rise as the US pays the on-going costs of veterans’ care and for interest on borrowing to pay for the wars.Moreover, the increases in the Pentagon base budget associated with the wars are likely to remain, inflating the military budget over the long run.”