Ambassador Thomas A. Shannon, a career member of the Foreign Service, class of Career Ambassador, currently serves as Counselor of the Department of State, a position he has held since 2013. Ambassador Shannon also served as Senior Advisor to the Secretary in 2013, U.S. Ambassador to Brazil from 2010 to 2013, and Acting Under Secretary for Political Affairs in 2011. Prior to that, Ambassador Shannon served as Assistant Secretary of State for Western Hemisphere Affairs from 2005 to 2009. From 2003 to 2005, he was Special Assistant to the President and Senior Director for Western Hemisphere Affairs on the National Security Council staff. Ambassador Shannon served in the Departments Bureau for Western Hemisphere Affairs as Deputy Assistant Secretary from 2002 to 2003 and as Director of Andean Affairs from 2001 to 2002. From 2000 to 2001, he served as the United States Deputy Permanent Representative to the Organization of American States and from 1999 to 2000, he was the Director for Inter-American Affairs on the National Security Council staff. His career as a Foreign Service Officer has also included service in Brazil, Gabon, Guatemala, Sao Tome and Principe, South Africa, and Venezuela. Ambassador Shannon received a B.A. from the College of William and Mary and an M.Phil. and D.Phil. from Oxford University.
https://diplopundit.net/2015/09/21/obama-nominates-fso-thomas-a-shannon-as-foggy-bottoms-new-p/
The day after the impeachment vote in the lower house of Brazils congress, one of the leaders of the effort, Senator Aloysio Nunes, traveled to Washington, D.C. He had scheduled meetings with a number of U.S. officials, including Thomas Shannon at the State Department.
Shannon has a relatively low profile in the media, but he is the number three official in the U.S. State Department. Even more significantly in this case, he is the most influential person in the State Department on U.S. policy in Latin America. He will be the one recommending to Secretary of State John Kerry what the U.S. should do as the ongoing efforts to remove President Dilma Rousseff proceed.
Shannons willingness to meet with Nunes just days after the impeachment vote sends a powerful signal that Washington is on board with the opposition in this venture...
http://www.counterpunch.org/2016/04/25/washingtons-dog-whistle-diplomacy-supports-attempted-coup-in-brazil/