By Subrata Ghoshroy, Bulletin of Atomic Scientists. October 6, 2020 In July, both the House of Representatives and the Senate passed their own versions of a defense authorization bill for 2021. By a wide majority, both chambers authorized more than $740 billion for defense spending next year. Tucked away in the Senate bill was $20.3 billion for missile defense, and that funding could make it into the final version that lands on the president’s desk. While $20.3 billion may not seem significant in a $740 billion budget, it is nevertheless a startling figure. What’s more, US taxpayers have invested nearly $200 billion on missile defense in the past two decades and another $100 billion in the decade before, with little to show for it.