(Andrew Selsky | AP file photo) In this Sept. 7 photo, a protester carries a Proud Boys banner, symbol of a right-wing group, while other members start to unfurl a large U.S. flag in front of the Oregon State Capitol in Salem, Ore. President Donald Trump didn't condemn white supremacist groups and their role in violence in some American cities this summer. Instead, he said the violence is a “left-wing" problem and he told one far-right extremist group to “stand back and stand by.” His comments Tuesday night were in response to debate moderator Chris Wallace asking if he would condemn white supremacists and militia groups. Trump's exchange with Democrat Joe Biden left the extremist group Proud Boys celebrating what some of its members saw as tacit approval.