What Trump's posture review means for U.S. nuclear weapons policy

Last week President Trump released his Nuclear Posture Review, the first update to the vital strategic document since President Obama's in 2010. What will it mean for the U.S. nuclear arsenal and its role in confronting today's global threats?

Four experts weigh in:

• Richard Haass, president of the Council on Foreign Relations: Unresolved nuclear debates rekindled
• Ivo Daalder, president of the Chicago Council on Global Affairs: Key Obama commitment retained
• Rebecca Hersman, director of the Project on Nuclear Issues at CSIS: New global threats addressed
• Frank O'Donnell, nuclear security fellow at Harvard's Belfer Center: Chain reaction risked in Asia