Yesterday, Oklahoma governor Mary Fallin signed into law a bill that approves the use of nitrogen gas for executions in the state. The method, which would effectively asphyxiate death row inmates by forcing them to breathe pure nitrogen through a gas mask, is meant to be the primary alternative to lethal injection, The Washington Post reports. Fallin and other supporters of the procedure say it's pain-free and effective, noting that the nitrogen would render inmates unconscious within ten seconds and kill them in minutes. It's also cheap: state representatives say the method only requires a nitrogen tank and a gas...