"The ultimate cost of the nation's engagements in Afghanistan and Iraq, on top of the incalculable personal toll on combatants and civilians, reflects a shift in how war has typically been financed. From the American Civil War through the Korean War, the U.S. government has mostly paid for its conflicts through taxes and war bonds. But in the post-September 11 era, U.S. military spending has been financed almost entirely through debt."