On October 3, 2009, more than 300 Taliban fighters overran Combat Outpost Keating, the outpost held by my reconnaissance troop of seventy-six cavalry scouts. During the eighteen-hour battle, the Taliban killed eight soldiers, wounded nineteen more, and burned our base to the ground. Describing my unit’s mission, President Obama asserted we had to “defend the indefensible.” This was the longest day of my life, but it only prefaced a struggle that has lasted for years.