Maine Senate candidate Graham Platner is pulling out of upcoming Democratic primary debates after Gov. Janet Mills (D), his main party rival for the seat held by Republican Sen. Susan Collins, suspended her bid this week. Platner, a progressive political outsider and oyster farmer, had been expected to face off in several upcoming debates with Mills and fellow Democrat David Costello. But his campaign told the Portland Press Herald on Friday he’s backing out to focus on defeating Collins in November. CBS 13, which planned to host one of the debates later this month, confirmed the change of plans. “I get the Platner camp’s logic in withdrawing from the 5 scheduled debates, yet this move cuts short important policy discussions and conversations and shortchanges Maine voters, most of whom haven’t fully focused on June’s primary election. I hope he’ll reconsider,” said Costello, a former Maine government official , in a post on the social platform X.…