Presidents from Turkmenistan, Iran, Kazakhstan, Azerbaijan and Russia at the Caspian Summit in Astrakhan, Russia, Sept. 29, 2014 (AP Photo/RIA Novosti, Alexei Nikolsky, Presidential Press Service).

As negotiations between Iran and the P5+1 countries—the U.S., France, U.K., Germany, Russia and China—over Tehran’s nuclear program enter the home stretch before their June 30 deadline, much of the attention in Washington and the media has been focused on the U.S. need to reaffirm its commitment to its Persian Gulf allies, in order to reassure them that an Iran nuclear deal would not compromise their security. In addition, however, the United States also needs to develop a strategy for managing the likely growth of Iranian influence in Central Asia and the South Caucasus that would follow any nuclear agreement. […]