Top Democratic officials and lawmakers are breaking with Democratic Maine Senate candidate Graham Platner as his past blunders and online history stack up. Platner’s ascendency to the top of the ticket in Vacationland broke with the Democratic establishment in Washington, D.C., and since Maine Gov. Janet Mills exited from the race, questions about whether he is the right choice to take on Sen. Susan Collins, R-Maine, have exploded. Much of that is fueled by scandals that have cropped up seemingly week after week, be it a tattoo on his chest of a Nazi symbol or inflammatory posts online. Some in the Democratic...