"He also has served as a senior adviser to four presidential campaigns. ... [Sullivan] has focused his practice on the growing intersection of global trade and investment and U.S. national security and foreign policies. He advises CEOs, general counsels, and other senior executives on U.S. sanctions and export controls, international trade disputes and regulation, and foreign investment in the United States, the Middle East, Russia, and other countries. His clients include major oil and gas companies, consulting, accounting, and financial services firms, petrochemical companies, and manufacturers. He has represented these clients before executive departments and agencies of the U.S. and foreign governments, as well as in litigation in the United States, where he has filed briefs and presented oral argument in courts across the country."