washington president barack obama say tuesday dismay violence divisiveness u.s. presidential campaign trail reference republican front-runner donald trump call leaders clean tone race hear vulgar divisive rhetoric aim women minorities americans look like us pray like us vote like obama say event capitol hill see misguide attempt shut speech however offensive may live country free speech one important right hold response attempt see actual violence hear silence many leaders obama speak americans five state ohio florida illinois missouri north carolina vote late round primaries select democratic republican presidential candidates november election trump draw wide criticism include within republican establishment campaign include call mexican immigrants rapists propose temporary ban muslims enter unite state clash recent days rally supporters protesters trump new york real estate magnate dismiss accusations fuel violent atmosphere obama say year campaign cycle accurate reflection unite state stop democratic president say describe atmosphere campaign vicious add behavior undermine democracy society even economy mitch mcconnell republican senate majority leader tell reporters trump call tuesday take opportunity recommend matter may trigger violent expressions conflict see rally might good idea condemn discourage mcconnell say decline comment trump response u.s. senators ted cruz texas marco rubio florida ohio governor john kasich challenge trump nomination suspect us recall intemperate word regret certainly obama say may blame others current climate us responsible reverse it obama call halt 'vicious tone violence campaign trail