As demonstrations have turned more heated and some activists have tried to block access to Trump's events, even his critics worry they may be helping the billionaire reality television star.
Democratic presidential candidate Bernie Sanders says it's appropriate to protest Trump but not to try to disrupt his rallies. A Republican group working to stop Trump warns that demonstrations play into an "us vs them" mentality.
Trump and his supporters, meanwhile, contend that demonstrators are depriving them of their constitutional rights to freedom of speech and assembly.