Texas Republican lawmaker to Beto O'Rourke:  Republican state Rep. Briscoe Cain drew fierce ire Thursday night for a gun-related tweet that many considered to be a death threat against Democratic presidential candidate Beto O'Rourke.   Twitter took the c o m m e n t down within hours because it violated a rule forbidding threats of violence and O'Rourke's campaign planned to report the tweet to the FBI, according to CNN. It's against federal law to threaten "major candidates" for president.   The online conflict came on the heels of two mass shootings in Texas and on the night that O'Rourke debated fellow ...