Texas has the nation's busiest executioner's chamber, and Harris County sends more convicted murderers to Huntsville's gurney than any other. Fighting this state-sanctioned killing machine are a handful of idealistic lawyers and the Texas Defender Service, a nonprofit organization dedicated to improving the quality of legal representation afforded to poor Texans charged with a capital crime or sentenced to death. The Defender Service became the main safety net for indigent inmates seven years ago after the federal government pulled the plug on funding for a system of legal resource centers that served the same purpose. In addition to representing defendants, the group, headed by University of Houston Law Center graduate Jim Marcus, churns out studies documenting how innocent people are being pulled into capital punishment's widening maw. "We are running full tilt at the edge of a cliff, the execution of the innocent," concludes a recent survey titled "Lethal Indifference." The study also notes that although two out of three capital cases nationwide are overturned for error, since 1995 the Texas Criminal Court of Appeals has reversed only eight of 270 decisions, the lowest reversal rate in the nation. That's about as underdog as it gets.