And why they want more. Become a member of the Vox Video Lab! http://bit.ly/video-lab Subscribe to our channel! http://goo.gl/0bsAjO Saudi Arabia and the US have a partnership that's been in the making for over seven decades. It started after World War II and survived the Iranian Revolution, the Cold War, the Gulf War, September 11, and the proliferation of conflicts across the Middle East. This whole time, the US has been selling weapons to Saudi Arabia -- now its number one customer. Saudis bought bombs, tanks, guns, and planes over the years to defend themselves from various threats. The US supplied those weapons because the Saudi’s threats have usually been a threat to the US as well. Today, there's a shift in the relationship. Saudi Arabia’s intervention in Yemen has created the worst humanitarian disaster in the world - and thrown the Middle East into chaos. The problem is, the Saudis are using US bombs to do it. Sources: US-Saudi arms agreements data: Stockholm International Peace Research Institute and the Defense Security Cooperation Agency Arab-Israeli arms race: Congressional Research Service and the Washington Institute for Near East Policy US-Saudi arms policy: Center for International Policy and the Brookings Institute Yemen airstrikes: Human Rights Watch Dahyan, Yemen, school bus bombing: Bellingcat Additional reading: https://www.newyorker.com/magazine/2018/04/09/a-saudi-princes-quest-to-remake-the-middle-east https://www.reuters.com/investigates/special-report/saudi-military/#graphic-sales https://www.fpri.org/article/2009/08/the-u-s-and-saudi-arabia-since-the-1930s/ https://www.foreignaffairs.com/articles/persian-gulf/1975-10-01/persian-gulf-arms-race-or-arms-control Vox.com is a news website that helps you cut through the noise and understand what's really driving the events in the headlines. Check out http://www.vox.com/. Watch our full video catalog: http://goo.gl/IZONyE Follow Vox on Facebook: http://goo.gl/U2g06o Or Twitter: http://goo.gl/XFrZ5H