Thomas R. Pickering was a fresh college graduate in 1953 when he braved the notoriously lengthy entrance process at the State Department, prolonged even further by an ongoing investigation of suspected communists in the agency’s ranks.

Although he was offered a job earlier than he expected, Mr. Pickering by then had enrolled in the graduate program of Tufts University’s Fletcher School of Law and Diplomacy in Medford, Mass. He later left for Australia on a Fulbright scholarship to the University of Melbourne, which was followed by three years in the Navy.

So it was 1959 when the 28-year-old finally became a Foreign Service officer — or, to use the better-known term, a diplomat…