Those not old enough to remember headlines from a conflict that was troubling the United States nearly half a century ago may not have paid much attention to the passing in Rome this week at age 86 of Madame Ngo Dinh Nhu. But she cut quite a figure in her day (in more ways than one, in her tight-fitting ao dai) and came to personify much of what was wrong with a South Vietnamese regime that the United States was struggling to prop up. Madame Nhu was married to the regime’s internal security chief, who in turn was the brother of President Ngo Dinh Diem. Diem came to power in 1955, the year following the accord that ended France’s war in Indochina and left Vietnam split between a communist north and non-communist south. Diem was a bachelor, and Madame Nhu functioned as the first lady of South Vietnam.

But she really functioned as much more than that. Strong-willed and outspoken, she was seen as a dominating influence on both her husband the security chief and her brother-in-law the president. Exactly how much influence she exerted on Diem outside of public view is impossible to say, but the outward indications were that it was substantial. Certainly she goaded the president toward the sort of hard-line and narrow-minded policies that made for a legitimacy problem in South Vietnam. The family was Catholic, and Madame Nhu especially became identified with intolerance toward the nation’s Buddhists. Some of the most searing images coming out of South Vietnam in the early 1960s were of Buddhist monks immolating themselves in protest. And among Madame Nhu’s most notorious comments were her reference to the protests as a “barbecue” and her offer to provide more fuel and matches if the Buddhists wanted to continue them.

By the last year of Diem’s rule, amid a growing Viet Cong insurgency and American frustration with the weaknesses of the regime that was supposed to stand in the communists’ way, Madame Nhu was seen as at least as big a part of the problem as President Diem. American patience with Diem might not have run out as soon as it did if Madame Nhu were not part of the picture. In the end, she was luckier than her husband and brother-in-law. When military officers overthrew the regime in 1963 in a coup that had received an American wink and nod, Ngo Dinh Diem and Ngo Dinh Nhu were killed. Madame Nhu was traveling in the United States at the time; she later lived out most of her exile in Italy.

The Diem regime was an example of an all-too-familiar pattern of a non-monarchical ruling family whose less desirable qualities undercut the regime’s legitimacy. This is all the more a problem when, as with Diem in Vietnam, the regime is looked to as an alternative to an insurgent opposition. The most obvious counterpart today is in Afghanistan, in which the image among Afghans of President Hamid Karzai is being formed in part by the activities of relatives such as his brother Ahmed Wali Karzai.

But before we place too much hope in what can be accomplished by ending a problem of conniving members of a privileged family, we should recall what happened in South Vietnam after Diem’s clan was overthrown. A succession of coups and military juntas followed over the next couple of years, as the communist insurgency continued to grow. Eventually continuity was achieved when Nguyen Van Thieu outmaneuvered his fellow generals and became president, but continuity—along with more than a half million U.S. troops at the peak of the Vietnam War—was not sufficient to keep the communists and their nationalist appeal from prevailing a decade later. The Madame Nhus and Ahmed Wali Karzais do present real problems of legitimacy and stability, but they often are part of conflicts whose outcomes are ultimately determined by forces much larger than themselves.