More than three decades apart, two political riots influenced the outcome of U.S. presidential elections. In 1968, protests at the Democratic National Convention in Chicago hurt Democrat Hubert Humphrey and helped Republican Richard Nixon eke out a victory. On Nov. 22, 2000, the so-called “Brooks Brothers Riot” of Republican activists helped stop a vote recount in Miami -- and showed how far George W. Bush’s supporters were ready to go to put their man in the White House. But the government reaction to the two events was dramatically different. The clashes between police and Vietnam War protesters in 1968 led...