So while Trump appeared flawless on the Cleveland stage Monday night, whether she intended it or not, her all-white ensemble displayed the kind of foreignness that is accepted by her husband’s political party. To many, that outfit could be another reminder that in the G.O.P. white is always right. Four years ago, Republicans fretted about trying to diversify their base, in the wake of Barack Obama’s clear voter mandate. This time around, with Trump at the top of the ticket, it’s obvious that ship has sailed. On Monday night, Melania Trump was a not-so-subliminal billboard for what’s looking like the...