After 37 years in office, Robert Mugabe’s odds of being removed from power by members of his ruling circle in Zimbabwe were slim. Research on authoritarianism suggests the 93-year-old president was well-positioned to live out his final days in office and join the ranks of the 80 post-World War II dictators who have died in office of natural causes.

The longer a dictator rules, the less likely he is to be toppled in a coup — that’s what history reveals. While concerns about succession loomed large in Zimbabwe, data show that older leaders (ages 65 and up) are at lower risk of losing power in a coup than are their younger despotic counterparts.

Another factor should have worked in Mugabe’s favor: the regime’s revolutionary origins. The shared experience of fighting against the white Rhodesian settler state in the 1960s and 1970s created a particularly strong bond between the civilian leaders of the Zimbabwe African National Union and the Zimbabwe Defense Forces.

Research shows that dictatorships borne out of such revolutionary struggles are exceptionally durable, because they are highly resistant to coups: Leaders of such revolutionary regimes rarely are overthrown by their own militaries. This shared revolutionary experience should have inoculated Mugabe from the military’s intervention.

What went wrong for Mugabe?

In short, he miscalculated. His decision to fire powerful vice president Emmerson Mnangagwa to position his wife’s succession violated two classic rules of authoritarian survival.

First, Mugabe’s moves to promote his wife, Grace Mugabe, upset the revolutionary values that underpinned his hold on power. Gen. Constantine Chiwenga, Zimbabwe’s army chief, made this breach explicit when he warned, “We must remind those behind the current treacherous shenanigans that when it comes to matters of protecting our revolution, the military will not hesitate to step in.” By purging a co-revolutionary in favor of his wife, Mugabe incited the armed forces to act.

Mugabe’s second mistake was thinking that he could orchestrate his wife’s accession to power. Since World War II, spouses have seldom succeeded their autocratic husbands. (One example might be Simone Duvalier’s custodial rule during the early years of Jean-Claude “Baby Doc” Duvalier’s presidency in Haiti, but the reality is that spousal takeovers are rare in dictatorships).

Efforts to install other family members as successors also set autocrats up to fall. The fate of former Egyptian president Hosni Mubarak illustrates this well. While hereditary successions do occur in autocracies, they tend to be successful only in monarchies or places where dictators have created their own political party, such as in Azerbaijan or Togo. By contrast, where parties predate a leader, elites are frequently able to override a ruler’s nepotistic succession selections.

Mugabe’s missteps ultimately led the military to intervene

Although the generals did not forcibly remove Mugabe from power, their actions were the crucial catalyst for his resignation. In autocracies, particularly highly repressive ones, information is scare. High levels of repression make it costly for citizens to express genuine opinions or display discontent.

This leads most people to overestimate the regime’s level of support, which disincentivizes anti-regime behavior. In other words, individuals are willing to act only if they believe that a sufficient number of their fellow citizens will do the same. The military’s moves, therefore, gave a signal of dissatisfaction that set off an “information cascade,” changing the decision calculus of the Zimbabwean elite about their willingness to remain acquiescent to Mugabe.

But what comes next for Zimbabwe? When longtime autocrats exit office, hope runs high that democracy will follow. As existing political science research makes clear, however, there is good reason to temper such optimism.

In fact, democracy results in only about 10 percent of dictatorships that end via coup. In more than half of these cases, the same regime persists. This suggests that it may very well be business as usual in Zimbabwe, just with a different person in the lead.

Was this even a coup?

The military intervention in Zimbabwe underscores a dynamic we have addressed in our work — that authoritarianism is evolving. The current uncertainty over whether this military action actually constitutes a coup is indicative of broader changes in authoritarian political dynamics.

In the past, aspiring autocrats orchestrated coups with little intention to mislead audiences, but this is no longer the case. Instead, today’s autocrats have learned that ambiguity and plausible deniability prevent domestic backlash, mute international criticism and make it difficult for opposition groups to mount a decisive response.

Should the fact that Mugabe’s ouster followed constitutional guidelines affect how we think about his removal? Our difficulty even labeling these recent events as a coup shows how the strategies of power grabs have evolved and are changing with the times.

A cautionary tale for other leaders

Mugabe’s story is also a cautionary one for other longtime autocrats. Dictators are especially prone to err precisely because they are dictators. This is particularly true for those regimes where power is highly concentrated in the hand of a powerful individual like Mugabe. Such strongmen surround themselves with “yes men,” who are promoted on the basis of loyalty rather than competence.

Having purged or intimidated key elites into subservience, these leaders convert their advisers into a cohort of sycophants. As a result, they then have limited access to accurate information about threats to their rule. Because their advisers are less skilled and less likely to pass along information the leader doesn’t want to hear, there is an outsized potential for mistakes.

Mugabe’s experience suggests that leaders like Russian President Vladimir Putin (17 years in power), Turkish President Recep Tayyip Erdogan (14 years in power) or Ugandan President Yoweri Museveni (30 years in power) may face similar risks of miscalculation. These leaders may one day misread the moods of their increasingly restless publics or miscalculate their allegiances. Although they have stacked the decks in their favor, it takes only one misguided decision to bring down the house of cards.

Andrea Kendall-Taylor is deputy national intelligence officer for Russia and Eurasia at the National Intelligence Council and nonresident senior associate in the Human Rights Initiative at the Center for Strategic and International Studies. She is also an adjunct professor in Georgetown University’s School of Foreign Service.

Erica Frantz is assistant professor of political science at Michigan State University. She specializes in the politics of dictatorship. Some of the data used in this research was funded by the National Science Foundation (BCS-0904478 and BCS-090463).