How Tear Gas Became a Staple of American Law Enforcement

On July 28, 1932, President Herbert Hoover dispatched federal troops and tanks to disperse the “Bonus Army,” tens of thousands of jobless World War I veterans and their families who’d been protesting in the nation’s capital. The troops used tear gas. Two men and two infants were reported dead. As one of the first major protests in which the American government used tear gas—which is considered a weapon of war—on its own citizens, the Bonus Army incident created public outrage, ruining any chance of Hoover’s reelection. For the chemical companies...