Much of the costs of the Iraq war and the Afghanistan war until FY2008 have been funded through supplemental appropriations or emergency supplemental appropriations, which are treated differently from regular appropriations bills. Senior congressional leaders have contended that those war costs, as much as possible, should go through the regular budget process, which provides for greater transparency. Determining the costs of the wars in Iraq and Afghanistan is complex. CBO has estimated that "war-related defense activities" in 2007 were "roughly $115 billion."