G raham Platner, a military veteran and oysterman from a small town near Maine's Acadia National Park, will run for U.S. Senate as a Democrat, he announced on Tuesday, in an effort to oust Republican Susan Collins, the five-term senator who is expected to run for reelection next year.

Graham Platner, a Democrat from Hancock County, joins a growing list of mostly little-known candidates to challenge Collins, who is seeking a 6th term.

Graham Platner, 40, from the Hancock County town of Sullivan, announced Tuesday he is running as a Democrat for the chance to take on the Republican senator.