WASHINGTON (AP) — Democrats’ hopes of reclaiming the U.S. Senate are colliding with a fight within their own party. In Maine, Senate Minority Leader Chuck Schumer has thrown his weight behind Gov. Janet Mills in a crucial race, but some of his Senate colleagues are backing insurgent candidate Graham Platner in a rebuke of his strategic vision. A similar dynamic is playing out in other battlegrounds, including Michigan and Minnesota, where progressives senators are endorsing non-establishment