Look, what the linked article ("Donald Trump’s most dangerous idea: His 'extreme vetting' of newcomers, including a values test, is anti-American," by S.E. Cupp) doesn't seem to appreciate are those Americans who believe that lax enough immigration will result in a religious-demographic shift over time to hardline sharia that would overthrow the Bill of Rights. Even softer versions of sharia would overthrow it.There are Muslims in the world who have openly stated that with their polygamous tenets and proclivity to reproduce at a higher rate than the typical non-Muslim American, they see exactly that happening: Muslims of a hardline-sharia mentality coming to dominate America and resulting in the overthrow of the US Constitution.
It's not an irrational view. Personally, I think that the Americanization of immigrants is real and that it has a strong tendency to change views and the rate of reproduction. It may take a generation or two, but it does happen in the vast majority of cases.
Meanwhile, there are real terrorists who would love to get into the US and do major damage. That's a fact. Is enough being done to keep them out? Who knows? Probably not.
What we really need to do is change our foreign policy away from neoconservatism to promoting peace and to helping other nations and peoples. Is that what Donald Trump is promoting? No. Neither is Hillary Clinton. She's an even worse warmonger — very reckless. She's backed hugely evil policies and practices and still does. What a sad, sad "choice"! Unbelievable, but here we are. Americans get what they deserve in their ignorance and foolishness.