Despite a persistent thrum of controversy around him, the Maine Democratic senate primary is still Graham Platner’s to lose. An Emerson College poll released Thursday found Platner leading his central opponent, Governor Janet Mills, by 55 percent to 28 percent among likely voters, a staggering 27 point gap ahead of the June 9 primary. 13 percent of voters said they were undecided in the race while four percent said they supported another candidate. The survey also took a look at the candidates’ potential matchups against Susan Collins in the fall, showing both Democrats with a slight edge over the Republican...