evidence: Retired Marine Gen. Jim Mattis, who resigned as President Trump's defense secretary nearly a year and a half ago over policy differences, has issued an extraordinary critique of the White House's handling of nationwide unrest, saying Trump has sought to divide Americans and warning against "militarizing our response" to the protests. [...] "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," Mattis wrote, referring to a series of events on Monday in which peaceful protesters were physically cleared from around the White House to make way for an appearance by the president, Bible in hand, outside a historic church. [...] The president responded to the criticism in a tweet, calling Mattis "the world's most overrated General," an insult Trump has fired off in the past.