Kralev is a former Financial Times and Washington Times correspondent. He witnessed firsthand the conduct of American diplomacy while accompanying four U.S. secretaries of state on their travels around the world — Hillary Clinton, Condoleezza Rice, Colin Powell and Madeleine Albright. His books include "Diplomatic Tradecraft" and "America’s Other Army."

Byrnes is a former U.S. ambassador to Northern Macedonia, and former deputy chief of mission in Greece and the U.S. Mission to the Organization for Security and Cooperation in Europe (OSCE) in Vienna. During her 30 years in the Foreign Service, she was also posted to Spain, Bolivia, Hungary and Turkey.

Burns is a former U.S. deputy secretary of state. A retired career ambassador in the Foreign Service, where he spent 32 years, he was also undersecretary of state for political affairs, assistant secretary for Near Eastern affairs, and ambassador to Russia and Jordan. He is a former director of the CIA.

Courville is a former ambassador to the African Union and senior director for African affairs at the National Security Council. A former civil servant, she also worked in the Office of the Secretary of Defense and the Defense Intelligence Agency.

Countryman is a former assistant secretary of state for international security and nonproliferation. During his 34-year Foreign Service career, he served in Serbia, Egypt, Greece, Italy and at the United Nations. He is chairman of the Arms Control Association.

Jacobs is a former assistant secretary of state for consular affairs. She was ambassador to Senegal and Guinea-Bissau and deputy chief of mission in the Dominican Republic. During her 34-year Foreign Service career, she also served in Ecuador, Egypt, Ethiopia, France, Mexico, Nigeria and Thailand.

Fitzpatrick is a former ambassador to Ecuador and head of the U.S. mission to the Organization of American States. During nearly 39 years in the Foreign Service, he was also deputy chief of mission in Peru and Paraguay, and deputy assistant secretary of state for Western Hemisphere affairs.

Miller is a former ambassador to Greece and Bosnia and Herzegovina, and special coordinator for Cyprus negotiations. During nearly 30 years in the Foreign Service, he was also posted to Thailand. He is a former CEO of the United Nations Association.

Wayne is a former assistant secretary of state for economic, energy and business affairs, principal deputy assistant secretary of state for European affairs and ambassador to Mexico and Argentina. His Foreign Service career spanned 40 years.

Fried is a former assistant secretary of state for European and Eurasian affairs, and former senior director for European affairs on the National Security Council. During his four decades in the Foreign Service, he was ambassador to Poland and also served in Russia and Serbia.

Ray is a former ambassador to Zimbabwe and Cambodia, deputy chief of mission in Sierra Leone, and consul-general in Ho Chi Minh City, Vietnam. A retired U.S. Army officer, he also served as deputy assistant secretary of defense for prisoners of war and missing personnel affairs.

Kubiske is a former ambassador to Honduras and deputy chief of mission in Brazil and the Dominican Republic. During her 35-year Foreign Service career, she also served in Mexico, China and Hong Kong, and was deputy assistant secretary of state for economic and business affairs.

Pickering is a former undersecretary of state for political affairs. During more than four decades in the Foreign Service, he was ambassador to Russia, India, Israel, Jordan, Nigeria, El Salvador and the United Nations. He also served as executive secretary of the State Department.

Kolker is a former assistant secretary for global affairs at the U.S. Department of Health and Human Services. During his 30-year Foreign Service career, he was ambassador to Uganda and Burkina Faso, deputy chief of mission in Denmark and Botswana, and also served in Britain and Sweden.

Reddick is a former ambassador to Niger, Gabon and São Tomé and Príncipe. During almost four decades in the Foreign Service, she also served in Burundi, Mauritania, Zimbabwe, China and Taiwan, and held several senior positions at the State Department in Washington, focusing on Africa and Asia.

Ricciardone is a former ambassador to Turkey, Egypt and the Philippines, and deputy ambassador to Afghanistan. During his 36 years in the Foreign Service, he was also posted to Britain and Jordan and held several senior positions at the State Department.

Zumwalt is a former ambassador to Senegal and Guinea-Bissau and deputy chief of mission in Japan. During 36 years in the Foreign Service, he was also deputy assistant secretary of state for East Asian and Pacific affairs, and served in China and the Democratic Republic of Congo.