If peaceful protests of this size would have come out in these major cities, I'm sure it couldn't have been ignored, as the U.S isn't authoritarian state. Most likely, it would have been calm and action against police violence would have been taken. Now it's just two parties, chimping out, hurting each other and clashing harder than before. Police officers and national guard wants to go home after their shift ends, see their family and live their life, just like the protestors. Black police officers trust their white squadmates and vice versa and so do any other race/ethnic group.