A black sergeant who was at the home of Harvard scholar Henry Louis Gates Jr. when he was arrested says he’s been maligned as an “Uncle Tom” for supporting the actions of the white arresting officer. Cambridge Sgt. Leon Lashley gave a letter to Sgt. James Crowley to give to President Barack Obama during their so-called beer summit with Gates on Thursday night at the White House. In the letter, which was also sent to CNN, Lashley says Gates “may have caused grave and potentially irreparable harm to the struggle for racial harmony.”