The deep divides that define politics in the United States are not restricted to policy or even cultural differences anymore. Americans no longer agree on basic questions of fact. Is climate change real? Does racism still determine who gets ahead? Is sexual orientation innate? Do immigration and free trade help or hurt the economy? Does gun control reduce violence? Are false convictions common?Employing several years of original survey data and experiments, Marietta and Barker reach a number of enlightening and provocative conclusions: dueling fact perceptions are not so much a product of hyper-partisanship or media propaganda as they are of simple value differences and deepening distrust of authorities. These duels foster social contempt, even in the workplace, and they warp the electorate. The educated -- on both the right and the left -- carry the biggest guns and are the quickest to draw. And finally, fact-checking and other proposed remedies don't seem to holster too many weapons; they can even add bullets to the chamber. Marietta and Barker's pessimistic conclusions will challenge idealistic reformers.