Democrats and Republicans are expected to spend about $1 billion getting their 2016 nominee elected. There’s a third group that will spend almost as much. It’s not a political party, and it doesn’t have any candidates. It’s the right-wing political network backed by the billionaire Koch brothers, Charles and David Koch, expected to spend nearly $900 million in 2016. The Kochs’ 2016 plans come as part of an effort to funnel hundreds of millions of dollars to conservative candidates and causes over the last four decades. The story of the Koch brothers and an allied group of billionaire donors is told in a new book by New Yorker reporter Jane Mayer, “Dark Money: The Hidden History of the Billionaires Behind the Rise of the Radical Right.” Mayer traces how the Kochs and other billionaires have leveraged their business empires to shape the political system in the mold of their right-wing agenda.