Why Mattis' verdict on Trump is devastating

Peter Bergen wrote for CNN on Jim Mattis' statement on President Trump and its implications.

A dam has broken. Former US Defense Secretary Jim Mattis -- who President Donald Trump has compared to one of his heroes, General George Patton -- on Wednesday issued a blistering statement saying, "Donald Trump is the first president in my lifetime who does not try to unite the American people -- does not even pretend to try. Instead he tries to divide us. We are witnessing the consequences of three years of this deliberate effort."

Mattis' statement came after police on Monday attacked peaceful protesters outside the White House with rubber bullets and a noxious gas so Trump could have a photo op with a bible outside St. John's Church near the White House.There are three reasons that Mattis' statement is so important. First, Mattis spent two years working closely with Trump as his first secretary of defense and so he is well-positioned to make the charge that the President has deliberately pursued a policy of division while in office. This is not a charge made by some armchair critic, but by one of the most senior members of Trump's cabinet who spent untold hours working directly with him.