Sen. Elizabeth Warren endorsed Graham Platner, an oyster farmer and combat veteran, over Maine Gov. Janet Mills in the Democratic primary to challenge Sen. Susan Collins this fall. Warren became the fourth senator to back Platner's populist campaign against the sitting Democratic governor.
The endorsement injects progressive energy into a primary race that pits a populist outsider against the state's established Democratic leadership. Platner's campaign has gained momentum with his populist agenda, though specific policy details were not outlined in the endorsement announcement.