Henderson was a career Foreign Service officer, born in Weston, Massachusetts, now a Boston suburb, in a house partially built by his carpenter father and in which Henderson now lives in retirement. His father joined the army to fight in the Philippine insurrection of 1899-1902 and again to take part in the Mexican border campaign of 1916, when Henderson was two years old. From Mexico he went to France to fight in World War I. He spoke often of other cultures, and although he "had a rather redneck attitude toward them," says Henderson, "he stirred my interest." His mother in turn stirred his interest in reading, much as Guevara's mother had influenced him. An uncle who spent many years in Latin America as a mining engineer stimulated Henderson's fascination with that particular area.
Henderson attended public elementary and high schools, then worked at various odd jobs—hospital orderly, rum-bottling plant employee, and apple picker—for four years. He was a gasoline-station attendant when a high-school teacher convinced him to try to go to college and helped him get a scholarship to Boston University. At the suggestion of a professor there, he went on to do graduate work on a fellowship at the Fletcher School of Law and Diplomacy at Tufts University. In 1941, he took the Foreign Service examination and was notified that he passed on the day before the Japanese attacked Pearl Harbor.
The State Department interceded with Henderson's draft board to have him excused from military service, then sent him to a series of consular jobs in small Latin American cities: Nogales, Mexico; Arica, Chile; and Cochabamba, Bolivia. In Bolivia, he rubbed bureaucratic fur the wrong way for the first of many times. When, for example, the ambassador in La Paz politely asked him how things were going in Cochabamba, he told him in detail—problems, frustrations, everything. The ambassador replied, quoting Charles Talleyrand: "Young gentleman, above all, not too much zeal." Later, the deputy chief of mission advised him to "take problems a little easier. . . . Ambassador Flack does not like excitement."
Henderson was assigned next to Washington, where in response to his request to develop his interest in economics he was loaned to the American Republics branch of the Department of Commerce. In many ways, it seems to have been the happiest and most successful time of his career. His private papers make clear that he reveled in the work, doing the intellectual, analytical tasks that were his forte. During this time, he helped draft point 4 of President Harry Truman's 1948 inaugural address, subsequently transformed into the famous Point 4 Program of technical assistance to developing nations. Henderson's superiors were delighted with his performance.
After the Commerce Department, Henderson served in economic assignments in Switzerland and in the State Department in Washington, then spent a year in a top-level training course called the Senior Seminar. From there, he went to Peru as the chief economics officer. Toward the end of the Peruvian assignment, when the ambassador was called away, Henderson took over the embassy as the charge d'affairs, bringing him to the attention of the Kennedy administration and leading to his appointment in 1963 as ambassador to Bolivia. By then, his was a life spun from the American dream, which for the purpose of legend made him the perfect opponent to Guevara, the staunch Americaphobe. Nevertheless, although Guevara must have known who the American ambassador was, there is no evidence so far that he gave him a moment's thought
Henderson began his tour in Bolivia with a confrontation with the president, then Victor Paz Estenssoro. When Henderson arrived in La Paz in 1964, four Americans from the embassy staff along with some German engineers and Bolivian supervisors were being held hostage in a room over the dynamite warehouse at a major Bolivian tin mine. Their captors were determined to release them only in exchange for two mineworker leaders arrested by the police. After presenting his credentials to the president in the courtly language of diplomatic ceremonies, Henderson finished his remarks by saying, "I have to inform your government that my government will hold your government responsible for the lives and property of its citizens now being held hostage in your country."
Paz Estenssoro was already working on the problem, and so was the new Johnson administration, which considered a rescue mission using Green Berets in helicopters until someone calculated that, at the altitude they would need to fly over the Bolivian mountains, each copter could at most carry one passenger. The actual escape, as Henderson recalls it, was much quieter and more bizarre. Several of his aides and the Catholic cardinal of La Paz held a conference with the miners at the mine, and while they met, Charles Thomas, the embassy consular officer, found the hostages unguarded and simply walked out with them. Whether or not it was quite that easy, the captives were released as a result of the conference, and Henderson was off to a flying start as an ambassador.
Henderson once had the temerity to question an order from Robert Kennedy via the Special Group and even won his case, at least in the short run. In career terms, he was probably more courageous than canny. Bolivia by 1964 had a place on the Special Group's list of endangered countries, and in such cases the group required embassies to report on the local communist threat every three months. Then, if the group believed the danger severe enough, it would take steps to help the control the situation. Believing that the Cuban government routinely sent materials to guerrillas in Peru through Bolivia via the Amazon River system, Henderson requested certain items, including small boats, to check that traffic. Because the group denied his request, he says he decided that "if this program can't provide me with what I say is necessary for achievement of my objectives then I don't see any point to the program." Called on the carpet in Washington by Averell Harriman and Robert Kennedy among others, he stood his ground: Without the materials, the reports were pointless. Furthermore, although Bolivia appeared on the Special Group's list of countries endangered by red subversion, communism in fact posed little threat to Bolivian stability, he stressed, pointing out that he had suggested the boats and other items only to keep supplies from going to underground groups in neighboring Peru. A half hour of heated discussion resolved only that his reporting requirement could be reduced from quarterly to yearly, but the experience added to his growing impression that the State Department "is not inclined to back up it missions. It is more influenced by Washington considerations than field considerations in the establishment of policy." He was far from the first or the last field officer to reach that conclusion.
Henderson's belief that communism presented little menace to Bolivian stability was not held universally in U.S. official circles. He does not remember the exact date of his meeting with Kennedy and Harriman, but it seems to have occurred in August or September 1964. In May 1965, the CIA's Office of Current Intelligence produced a memorandum entitled "Instability in Latin America" that ranked critical countries, placing Bolivia second after the Dominican Republic. Although in the intervening months, Barrientos and his military colleagues had toppled the civilian government, the new regime did not put at rest the minds of CIA analysts. They said that, "partly because of dissention among the military, the political situation is highly unstable and could degenerate promptly into civil war. Communists and leftist extremists are armed and determined not to permit a prolongation of the Barrientos regime." As we now know, Barrientos held precisely this same view.