How Tear Gas Became a Favorite Weapon of U.S. Border Patrol, Despite Being Banned In Warfare

As the Trump administration continues to defend firing tear gas into crowds of asylum seekers, we look at the history of tear gas, which is banned in warfare but legal for federal authorities and police to turn on civilians. Border authorities' use of tear gas has spiked under the Trump administration, with the agency's own data revealing it has deployed tear gas over two dozen times this year alone. Customs and Border Protection told Newsweek Tuesday it began using tear gas under the Obama administration in 2010. The agency's use of tear gas has now reached a seven-year record high. We speak with Stuart Schrader, lecturer in sociology at Johns Hopkins University. He has studied how tear gas went from a weapon of war used in Vietnam to being deployed by law enforcement at home. His forthcoming book is titled "Badges Without Borders: How Global Counterinsurgency Transformed American Policing."