ClimateWire: Political candidates in Massachusetts are attacking Cape Wind, making the nation’s first federally approved offshore wind project a target of liberals and conservatives seeking seats in Congress and the governor’s office. Complaints are centered on the cost of power to be produced by the 130 turbines planned for construction 5 miles off the sandy shores of Cape Cod. It is an argument echoed in elections around the country that warn voters of climate policies that might raise the cost …