Barron Trump is, rightly, a mystery to the American public. Donald Trump’s youngest child was only 10 when his father was elected president in 2016, and it’s generally considered poor form for journalists or politicians to criticize the president’s minor children. We can see that Barron is tall — his father once said the teen was already towering over him at six-foot-seven — and that’s pretty much all we know. But now Barron, who turned 18 in March...