The fight for Christmas took a hit this week when politics bigfooted a troupe of adorable little ballet dancers performing “The Nutcracker.” MSNBC’s Chris Matthews is scheduled to interview President Obama on Thursday night at American University as part of the “Hardball College Tour.” MSNBC approached AU to host the chat, and officials jumped at the chance for a free, hour-long commercial for the university and its students. But the interview, announced Tuesday morning, abruptly kicked the Ballet Petite’s rehearsals of”The Nutcracker” out of AU’s Greenberg Theatre. That didn’t sit well with the ballet school’s staff, teachers and parents who...