Democratic Chicago Mayor Brandon Johnson evoked an unexpected name Monday while discussing the reason behind a spate of gun violence over the weekend — former President Richard Nixon. Police said Monday that over 100 people had been shot — 19 fatally, including one police officer — over the July 4th holiday weekend across Chicago. Johnson hosted a press conference on Monday to address the incidents and more broadly Chicago’s problems with violence and crime, and appeared to claim that the reason the city is suffering from gun violence was because Nixon won in 1968 after then-President Lyndon B…