Another scandal rocked Graham Platner’s U.S. Senate campaign a week before the primary he has already effectively won, raising concerns among Democrats in Maine and Washington about what else may be hiding in the Sullivan oyster farmer’s past. Platner is seen as the only viable Senate candidate on the June 9 primary ballot after Maine Gov. Janet Mills suspended her campaign, and there's no mechanism to select another nominee against Republican Sen. Susan Collins at this point, unless Platner quits.