Barack Obama to visit Dallas shootings scene as fresh protests deepen America’s divides

He was sharply criticised by Heather Mac Donald, an influential rightwing author who is a leading proponent of the so-called “Ferguson effect”, which holds that crime has spiked since the unrest in Missouri because frontline police officers have been pushed into a retreat.

Accusing Obama of “attacking the very foundation of civilisation” by giving credibility to Black Lives Matter, Mac Donald told the conservative radio host Rush Limbaugh the president had “lied to the nation” and “we see the results”, apparently referring to the Dallas shootings.