HUNTSVILLE -- On Feb. 25, I watched my government kill a killer. Texas' 298th execution was the first death I had seen, but the other reporters and prison officials who were there had each observed more than 100 state killings. With the experience of 306 executions in 20 years, Texas carries them out with machine-like precision. Regular witnesses refer to them as "clinical." The executions take place in the Walls prison unit, a crumbling red brick behemoth dating back to 1848. The unit takes up several blocks of downtown Huntsville and bears little resemblance to a modern-day prison. It looks...