Since jihadism is muslim-borne social trouble caused by pseudo-arabism so naturally a government has to be vigilant about entrants with arabic names or attire.
Donald Trump is trying just that. The very first opposition to his discrimination with Muslims had come by the most dominant hindus and jews in America such as Sunder Pichai and Mark Zuckerberg followed by a plethora of Trump-baiters. People dislike discrimination through this internet age.
Still every neighborhood refuses any untoward entrants. So is the case with the United States of America. You just cannot take a sovereign country for granted. Donald Trump is duty bound for doing whatever he promised for getting democratically elected as US President.