What we can learn from 70 years of coups

The sudden coup d'etat attempt in Turkey was shocking partially because coups are less frequent than they used to be.

A few decades ago, there were about 15 coup attempts or confirmed coup plots every year, according to data compiled by the Center for Systemic Peace. Today, there are still about six coups every year, or eight counting alleged coups reported by regimes that researchers say may not have actually happened.

But coup plots are far less likely to lead to attempted coups, and attempted coups are far less likely to be successful than they were a few years ago. Only about a third of plots and 40 percent of attempted coups end up being successful, according to the data.

The world has seen only 18 attempted coups since 2010, and only four successfully installed a new leader for at least a month. That's not a great success rate, and it's even lower when counting confirmed coup plots that were cut off before they could come to fruition.

Why are successful coups so unlikely these days? One reason is that the world has changed, with governments shifting towards democracy, said Monty Marshall, director of the Center for Systemic Peace.

"Most coups are just changes of autocratic leadership," Marshall said. "We're in a democracy-dominant global system, and coups have become less frequent as governments have become more democratic."

Military forces are also less likely to intervene either to oust a bad leader or crack down on popular uprisings. Leaders are more likely to be forced to resign by protesters in the streets than they were in earlier decades, according to the data.

"When you wanted to get rid of a bad president, usually the military stepped in to get rid of the president. Now we have forced resignations and popular upswells of dissent with people taking to the streets," Marshall said. "It's more prevalent for the military to refuse to become politically involved."

Coups tend to be bad news for the local economy, but they can also be driven by economic underperformance. They can affect gross domestic product for years after the event itself.

Thailand is the country that has seen the most successful coups since 1946 (10), according to the data, followed by Bolivia (eight), Syria (eight), Argentina (seven) and Haiti (six).

Coups in Thailand are among the most likely to succeed, with 10 of the 16 attempted coups or coup plots succeeding (not counting questionable alleged coups). Bolivia has managed to suppress 14 coups, behind only Iraq and Sudan, which have each avoided 20 out of 24 coups.

In countries like Turkey it's harder to pull off a coup then in younger, less established countries, Marshall said. The jury is still out on whether the events this month should be counted as an attempted coup in the data set. The circumstances are "fishy," he said.

"It looks more like the government was moving against their purge list and they were acting to defend themselves, knowing that once the government was moving against them they would have no chance," he said. "That can happen when the government moves against opposition that is well entrenched in the military."

What counts as a coup

To be included in the dataset, a coup is defined as a "forceful seizure of executive authority and office by a dissident/opposition faction within the country's ruling or political elites that results in a substantial change in the executive leadership and policies of the prior regime."

So things like "self coups" — when a leader subverts a constitutional government and makes it autocratic — are not counted. Foreign invasions, ousters by rebel forces, assassinations and resignations due to popular pressure are also not counted as coups (although they are tracked in the same data set).