Regardless of which party the victims belong to, this kind of violence is unacceptable. We do not yet know whether the shooter obtained the gun legally, had a history of violence or mental illness. That said, there are people, including Republicans, who like the NRA, believe that anyone who wants one should be allowed to have a gun and allowed to have any kind of gun they want. Some reports say the gunman had an assault rifle. If so, they may want to rethink this position now that they have become targets.