James Garfield Broadnax was executed by lethal injection last night, April 30, at Texas State Penitentiary, Rolling Stone reports. Broadnax had been convicted of double murder in 2009, at the age of 19, and his case had become a cause célèbre in ongoing debates over the use of rap lyrics in court. As recently as March, a number of artists including Travis Scott , Young Thug , and Killer Mike had petitioned the Supreme Court to halt the execution. Broadnax was 37. Broadnax and his cousin, Demarius Cummings, were arrested in 2008, after an attempted carjacking resulted in the deaths of producers Stephen Swan and Matthew Butler. Broadnax quickly confessed to the murders and even bragged about them on the local news—though he was high on PCP-laced weed at the time. Broadnax was found guilty by a predominantly white jury, but before he could be sentenced, prosecutors entered into evidence 40 pages of handwritten rap lyrics that had been found in his car.…