I think Trump is misunderestimating the American people in much the same way as Obama. Where the president seems to fear the possibility of widespread violence against Muslims (or those perceived as such), the presidential candidate evidently sees a widespread consensus that Muslims are so likely to be dangerous that it is unduly risky to allow any to enter the country.

This seems to me to get recent history wrong. “If this guy doesn’t look like an Arab terrorist, then nothing does,” the ticket agent who let 9/11 hijacker Muhammad Atta pass through security recalled thinking, “but it’s not nice to say things like this.” Neighbors of the San Bernardino terrorists noticed peculiar goings-on, but didn’t report them to authorities.

It seems that many Americans, out of a misplaced reluctance to discriminate by religion, have difficulty making the distinctions — discriminations needed to identify terrorists. That’s a problem not easily solved, and Obama’s and Trump’s misunderestimations aren’t helping.