The Texas Supreme Court late Thursday halted the execution of Robert Roberson hours after it was set to take place, capping a flurry of litigation filed that same day by Texas state lawmakers in a last-ditch gambit to stop the state from killing a death row inmate they believed was most likely innocent.The order was a stunning eleventh-hour victory for Roberson and for the state lawmakers who opposed his execution and turned to novel legal maneuvers in an effort to buy him more time.The stay arrived in response to a separation-of-powers conflict touched off by a group of Texas lawmakers when they subpoenaed Roberson the night before he was set to be put to death. The unprecedented step sought to give the man a final…