A growing number of states are moving forward with legislation to exempt them from new federal gun controls and, in some cases, brand as criminals anyone who tries to enforce them. While many of the bills are considered symbolic or appear doomed to fail, the legislative explosion reflects a backlash against legislative and regulatory efforts in Washington to tamp down on gun violence. As of this week, at least 28 states had taken up consideration of gun bills this year, according to new data compiled by the National Conference of State Legislatures. More than 70 bills have been put forward...