“I have watched this week’s unfolding events, angry and appalled,” Mattis wrote in a blistering statement to The Atlantic.
“The words ‘Equal Justice Under Law’ are carved in the pediment of the United States Supreme Court. This is precisely what protesters are rightly demanding. It is a wholesome and unifying demand — one that all of us should be able to get behind. We must not be distracted by a small number of lawbreakers," he added.
He also accused the president of dividing Americans and pitting them against each other.
“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. We are witnessing the consequences of three years without mature leadership. We can unite without him, drawing on the strengths inherent in our civil society. This will not be easy, as the past few days have shown, but we owe it to our fellow citizens; to past generations that bled to defend our promise; and to our children," Mattis added.
He also contrasted the Nazi ideology to Americans values of unity and cooperation.
“Instructions given by the military departments to our troops before the Normandy invasion reminded soldiers that ‘The Nazi slogan for destroying us … was "Divide and Conquer." Our American answer is 'In Union there is Strength.'" We must summon that unity to surmount this crisis — confident that we are better than our politics.”
He also commented on the of violence against peaceful protesters on Monday night so that Trump could walk to and take a photo in front of the St. John's Episcopal Church in Washington, DC.
"When I joined the military, some 50 years ago,” he wrote, “I swore an oath to support and defend the Constitution. Never did I dream that troops taking that same oath would be ordered under any circumstance to violate the Constitutional rights of their fellow citizens — much less to provide a bizarre photo op for the elected commander-in-chief, with military leadership standing alongside."
The former defense secretary also stressed the importance of only using the military on "very rare occasions."
“We must reject any thinking of our cities as a ‘battlespace’ that our uniformed military is called upon to ‘dominate.’ At home, we should use our military only when requested to do so, on very rare occasions, by state governors. Militarizing our response, as we witnessed in Washington, DC, sets up a conflict — a false conflict — between the military and civilian society. It erodes the moral ground that ensures a trusted bond between men and women in uniform and the society they are sworn to protect, and of which they themselves are a part. Keeping public order rests with civilian state and local leaders who best understand their communities and are answerable to them," Mattis noted.
Trump on Monday said he would deploy US military to states that don't use the National Guard in sufficient numbers to dominate the streets as protests against police brutality rage across America.