Republican Olympia Snowe of Maine railed against obstructionist politics and partisanship in the Senate. Now she’s continuing to work for civility and compromise from outside the Senate. She writes in a new book, “Fighting for Common Ground,” about her 34 years on Capitol Hill as Congress went from a place where parties worked to forge compromise to today’s corrosive politics. She says Washington can change and that voters must demand it. The release of her book this week coincides with an online push to get voters to turn up the heat on lawmakers through the Bipartisan Policy Center, a nonprofit think tank. Weinstein Books, a member of the Perseus Books Group, is donating a portion of her book revenues to the organization.