What is the origin of left and right in politics? The traditional answer is that these ideas derive from the French National Assembly after 1789, in which supporters of the King sat on one side and those of the revolution on the other. Yuval Levin in The Great Debate, however, argues not for seating but for ideas: that left and right enter the Anglo-American political bloodstream via the climactic public clash in the 1790s between Edmund Burke and Thomas Paine, the prime movers in a pamphlet war that convulsed opinion and engaged readers on two continents.