The former co-leader of Mayer Brown's national security practice will be the Trump administration's nominee to serve as the U.S. ambassador to Russia, the White House said on Friday.

John Sullivan John Sullivan

John J. Sullivan has been serving as the U.S. Senate-confirmed second-in-command at the U.S. State Department since mid-2017. Sullivan would succeed Jon Huntsman as ambassador. Huntsman, who resigned in August, is reportedly mulling a run as governor of Utah.

Sullivan briefly served as the acting secretary of state in 2018 after the departure of Rex Tillerson, the former Exxon chief executive. Sullivan has held senior posts, earlier in his career, at various federal agencies, including the Justice Department and Commerce Department, the White House said.

As the number two at State, Sullivan "leads a pair of ongoing dialogues with Russia – focused on counterterrorism and strategic security – and he worked on issues involving that country in prior roles in government and in private legal practice", The Wall Street Journal reported.