Energy, Sanctions, and Commodities (ESC) is one of seven issue-oriented organizations of the Bureau of Economic, Energy and Business Affair at the U.S. Department of State. ESC is headed by Deputy Assistant Secretary Robert F. Cekuta. ESC formulates and implements U.S. foreign policy relating to energy, sanctions, and commodities. The international aspects of energy with which ESC deals are critical to U.S. national security, because U.S. has only 2% of proven world oil reserves and its imports supply roughly meets only half of U.S. oil needs. In addition, ESC also plays a leading role in negotiating and implementing the Kimberley Process certification scheme, which seeks to fight against the use of rough conflict diamonds to finance rebel movements against legitimate governments.