In years to come, historians will ask important questions about the role of power in the Iraq and Afghanistan campaigns. Specifically, they will ask how Afghanistan became America's longest war, and how we were able to invade and leave Iraq within the bookends of the Afghan conflict. It is especially hard to understand how we recovered power in Iraq after Abu Ghraib and a fractious civil war. Although arguments over what we accomplished in Iraq will endure for years, we regained enough power to leave Iraq without a debate. We subsequently attempted to carry the momentum of the Iraq counterinsurgency campaign to Afghanistan in 2009, but still struggle to achieve something resembling the ambiguous success in Iraq. The disappointment in Afghanistan goes beyond a misapplication of what worked in Iraq; the power equation between Iraq and Afghanistan was altogether different. In war, power wins. Individuals often confuse military might with power, but in reality, there are many power factors relevant to the outcome of war. Power flows from diplomatic, political, and economic strength as well as strategic, operational, and tactical effectiveness. Sound analysis of warfare will avoid focusing on any one of these sources, and will instead examine relevant power, which accounts for the interplay of power sources within the context of conditions and rivals in a war. In both Iraq and Afghanistan, our relevant power ebbed and flowed due to changes in our power sources. We did not have adequate power to influence conditions in Iraq before 2007 due