By Brendan O'Brien (Reuters) - Some 20 demonstrators were arrested on Thursday outside a Donald Trump campaign rally in southern California, where the Republican presidential front-runner vowed to his supporters to get tough on illegal immigration if elected. Demonstrators smashed the window of a police squad car, marched in protest and blocked traffic as police in riot gear tried to disperse the crowd outside of the county fair grounds in Costa Mesa, California, according to local media and the Twitter account of the Orange County Sheriff's Department. The department said on its Twitter account that about 20 arrests were made and that no major injuries were reported.
