In making the case for his nuclear-arms-control deal with the Islamic Republic of Iran, President Obama has confronted Congress with a stark choice. "There really are only two alternatives here," he declared at last week's press conference. "Either the issue of Iran obtaining a nuclear weapon is resolved diplomatically through a negotiation or it's resolved through force, through war."

This binary argument is so central to his administration's case that the president provided a second formulation: Without the deal, he said, "we risk even more war in the Middle East, and other countries in the region would feel compelled to pursue their own nuclear programs, threatening a nuclear arms race in the most volatile region in the world."