Built decades ago, many of our nuclear weapons systems must be upgraded or replaced.  Is it worth spending hundreds of billions of dollars, however, to maintain American nuclear might? The Cold War is long over and lawmakers are looking for budget cuts, yet nuclear threats from the likes of North Korea and Iran seem to only grow.  Experts Jeffrey Lewis, founder of armscontrolwonk.com, and Elbridge Colby, a research analyst at the Center for Naval Analyses, discuss the future of the American nuclear arsenal and take listeners’ calls. To join the conversation, call 312-923-9239. And on Global Notes, contributor Catalina Maria Johnson and Jerome listen to music by artists who are hoping to change the world.