Last week Rep. Nancy Pelosi warned President Donald Trump that if he declared an “emergency” to build a wall, “think what a president with different values can present. … Why don’t you declare (the epidemic of gun violence in America) an emergency, Mr. President? I wish you would. … A Democratic president can declare emergencies as well.” Her fellow Democrats Sen. Kamala Harris and Sen. Elizabeth Warren quickly agreed. Warren tweeted: “Gun violence is an emergency. Climate change is an emergency. …” Yikes. Not every problem in America should be declared an emergency – or used by a president to...