On Aug. 12, leaders of the five Caspian Sea littoral states—Russia, Iran, Kazakhstan, Azerbaijan and Turkmenistan—gathered in the Kazakh port city of Aktau to sign the Convention on the Legal Status of the Caspian Sea. The agreement ended decades of uncertainty over the Caspian Sea’s status, clarifying the boundaries between each party’s territorial waters. And while the agreement left open the key question of ownership over the rich oil and gas deposits lying under the Caspian’s seabed, it provides a framework for these five countries to work out arrangements for joint exploration and drilling, as well as long-stalled pipeline projects. […]