ANAHEIM, CA - MAY 25:  Pro Trump hats lie on the ground before police horses and a Mexican flag as protesters and supporters clash outside a campaign rally by presumptive GOP presidential candidate Donald Trump at the Anaheim Convention Center on May 25, 2016 in Anaheim, California.  Previous visits by the candidate to Orange County have sparked in protests that resulted in some arrests. The presidential candidates are campaigning in Southern California for the June 7 California primary.  (Photo by David McNew/Getty Images)