After the massacre of five Dallas cops, during a protest of police shootings of black men in Louisiana and Minnesota, President Obama said, "America is not as divided as some have suggested." Former D.C. Police Chief Charles Ramsey, an African-American, says we are "sitting on a powder keg." Put me down as agreeing with the president. For when a real powder keg blew in the '60s, I was there. And this is not it. In 1965, the Watts area of Los Angeles exploded in the worst racial violence since the New York draft riot of 1863 when Lincoln had to...