Republicans are accusing Democrats of wanting to raise senior citizens’ taxes in a new ad campaign targeting the most important Senate races in the midterm elections. “Alaska seniors are struggling, and Mary Peltola would make it worse,” a new ad from the National Republican Senatorial Committee says of Ms. Peltola, 52, a former House lawmaker representing Alaska. Ms. Peltola is running against two-term Republican Sen. Dan Sullivan, 61. “Mary Pe…