Turkey has remained opposed to Finland and Sweden's application to join NATO, saying it wants "concrete steps" to be taken regarding the terrorist organizations that threaten Turkey's national security. Will Turkey's objection present a serious obstacle for Sweden and Finland's NATO membership? What would the success or failure of NATO expansion mean for the military alliance and the world?

To explore these questions and more, we've invited Serkan Oral, a political analyst & writer in Turkey; Professor Robert Kelly from the Department of Political Science of Pusan National University; and Pavel Felgenhauer, Russian defense analyst.