Graham Platner speaks at a press conference announcing Maine AFL-CIO endorsement of him in Portland on Friday, May 1, 2026. (Brianna Soukup/Staff Photographer) " data-image-caption="Graham Platner speaks at a news conference announcing the Maine AFL-CIO endorsement of him in Portland on Friday. (Brianna Soukup/Staff Photographer) " data-large-file="https://www.pressherald.com/wp-content/uploads/sites/4/2026/05/43574849_20260501_PlatnerCollins_15.jpg?w=780"> Graham Platner speaks at a news conference announcing the Maine AFL-CIO endorsement of him in Portland on Friday. (Brianna Soukup/Staff Photographer) When Gov. Janet Mills suspended her U.S. Senate campaign last week, making political newcomer Graham Platner the presumptive Democratic nominee, campaign donors responded enthusiastically. Since Mills announced her decision last Thursday, Platner...