The Kansas-based conglomerate Koch Industries, rooted in oil refining, generates an estimated $100 billion in annual revenue, but it's how the libertarian Kochs spend their money that draws attention. The brothers Koch, among the richest men in America, continue to use their massive fortunes to support a slew of conservative causes, and the 2010 midterms may have been their biggest payoff yet. Their funding helped the Tea Party grow from a grass-roots phenomenon into a powerful movement that fueled the Republicans' return to the majority in the House. It also sparked a growing chorus of criticism from the left about the corrupting influence of corporate money in politics.