But by the time they returned to the other bank, government troops pursuing them had arrived. According to one survivor, Lumumba’s famous eloquence almost persuaded the soldiers to let them go. Events like this are often burnished in retrospect, but however the encounter happened, Lumumba seems to have risked his life to try to rescue the others, and the episode has found its way into film and fiction.

His legend has only become deeper because there is painful newsreel footage of him in captivity, soon after this moment, bound tightly with rope and trying to retain his dignity while being roughed up by his guards.

Patrice Lumumba had only a few short months in office and we have no way of knowing what would have happened had he lived. Would he have stuck to his ideals or, like too many African independence leaders, abandoned them for the temptations of wealth and power? In any event, leading his nation to the full economic autonomy he dreamed of would have been an almost impossible task. The Western governments and corporations arrayed against him were too powerful, and the resources in his control too weak: at independence his new country had fewer than three dozen university graduates among a black population of more than 15 million, and only three of some 5,000 senior positions in the civil service were filled by Congolese.

A half-century later, we should surely look back on the death of Lumumba with shame, for we helped install the men who deposed and killed him. In the scholarly journal Intelligence and National Security, Stephen R. Weissman, a former staff director of the House Subcommittee on Africa, recently pointed out that Lumumba’s violent end foreshadowed today’s American practice of “extraordinary rendition.” The Congolese politicians who planned Lumumba’s murder checked all their major moves with their Belgian and American backers, and the local C.I.A. station chief made no objection when they told him they were going to turn Lumumba over  render him, in today’s parlance  to the breakaway government of Katanga, which, everyone knew, could be counted on to kill him.

Still more fateful was what was to come. Four years later, one of Lumumba’s captors, an army officer named Joseph Mobutu, again with enthusiastic American support, staged a coup and began a disastrous, 32-year dictatorship. Just as geopolitics and a thirst for oil have today brought us unsavory allies like Saudi Arabia, so the cold war and a similar lust for natural resources did then. Mobutu was showered with more than $1 billion in American aid and enthusiastically welcomed to the White House by a succession of presidents; George H. W. Bush called him “one of our most valued friends.”

This valued friend bled his country dry, amassed a fortune estimated at $4 billion, jetted the world by rented Concorde and bought himself an array of grand villas in Europe and multiple palaces and a yacht at home. He let public services shrivel to nothing and roads and railways be swallowed by the rain forest. By 1997, when he was overthrown and died, his country was in a state of wreckage from which it has not yet recovered.