Platner, a Democrat who served as a Marine in Iraq and the Army in Afghanistan, says the "oligarchy is the enemy."

Graham Platner wants to oust Sen. Susan Collins — and disrupt national Dems’ plans to unite around Gov. Janet Mills.

A largely unknown oysterman and military veteran, Graham Platner garnered widespread attention this week when he launched a U.S. Senate campaign to try to unseat long-time Republican U.S. Sen. Susan Collins.