Is the Iran nuclear deal effectively dead? Three questions.

Escalating tensions between the U.S. and Iran have put renewed focus on what remains of the Iran nuclear deal – and what, if anything, might ultimately replace it.

The Iran nuclear agreement, formally known as the Joint Comprehensive Plan of Action (JCPOA), took effect in January 2016. Negotiated between Iran and the five permanent members of the U.N. Security Council – China, France, Russia, the United Kingdom, and the United States – plus Germany, the deal imposed restrictions on Iran’s civilian nuclear enrichment program in return for relief from nuclear-related...