Maine's Democratic Senate primary tests age and ambition as Mills faces a younger challenger

In Maine’s June 9 Democratic primary, 78-year-old Gov. Janet Mills faces 41-year-old Graham Platner, highlighting a Democratic split between experienced incumbency and a new generation of progressives seeking to unseat Sen. Susan Collins. Platner, backed by Bernie Sanders, pushes bold reforms while Mills emphasizes experience and a one-term pledge. The race also hinges on Platner’s past online controversies and the broader question of whether seniority or freshness best serves Maine in a possible bid to shape Senate control; outside groups are preparing for a tough general election wherever the primary goes.