WASHINGTON — Former logger and onetime Maine Senate President Troy Jackson is on course to replace accused rapist Graham Platner as the Democratic Senate nominee following a series of party caucuses over the weekend. As results from the Pine Tree State’s 16 counties showed Jackson running away with the committed delegate count, would-be contenders Nirav Shah, former head of the state’s Center for Disease Control and Prevention; state Secretary of State Shenna Bellows; Maine Beer Co. founder Dan Kleban; and ex-congressional hopeful Jordan Wood dropped out one by one. “Today, I am stepping aside, and I am doing it for...