Trump has fallen to 5 percentage points behind Hillary Clinton in matchup polls. That is still a lot better than he was doing earlier in the spring, but he's now heading in the wrong direction. And Clinton has a predictable likely bounce coming now that she has mathematically clinched the nomination and will soon receive endorsements from the remaining neutral high-profile Democrats including Barack Obama, Joe Biden and Elizabeth Warren — support that will be capped by a made-for-TV White House visit.