Nearly 70.8 million people worldwide were displaced by violence last year, according to a report that the U.N. High Commissioner for Refugees’ office released last week. That’s the highest total number for any year ever and the highest in relative terms since World War II. Many of the crises behind this grim figure—which includes both international refugees and internally displaced people—come as no surprise: the ongoing wars in Syria, Afghanistan, and Somalia; the long-term displacement of Palestinians; the persecution of Myanmar’s Rohingya; the implosion of Venezuela; and the violence in Central America’s Northern Triangle that has created a humanitarian crisis on the U.S. southern border.

But the world’s largest new population of displaced people results from a conflict that has received shockingly little international attention: More than 1.5 million people were displaced by violence in Ethiopia last year, nearly all of them internally. This increase doubled the total number of displaced people in the country.

The fact is surprising in part because Ethiopia is enjoying a period of unusually good publicity. Prime Minister Abiy Ahmed, who took over in April 2018, has earned international praise for an ambitious reform agenda that has included freeing thousands of political prisoners, reining in the country’s security services, lifting a state of emergency and restrictions on the media, and resolving a long-running border conflict with neighboring Eritrea. But Monday’s headlines, which saw the killing of a general accused of plotting a coup attempt, suggest the government’s position is fragile. Ethiopia’s current situation brings to mind Alexis de Tocqueville’s famous warning that the most dangerous moment for a bad government is when it starts to reform.

Now that the government is in a moment of transition, ethnic conflict is surfacing. Much of the worst of the crisis has occurred in the country’s southern region, where hundreds of thousands of people have been displaced by fighting between the Oromo and Gedeo ethnic groups. Abiy is Oromo, and many of his reforms are meant to address the marginalization of several ethnic groups, including his own. But observers say the reforms have emboldened communal violence by Oromos. Tensions between the two groups are not new but have intensified in recent years due in part to competition over scarce farmland and resources. (Ethiopia has one of the fastest-growing populations in the world.) Lynchings, rapes, and beheadings have been reported.

Yohannes Gedamu, an Ethiopian political scientist at Georgia Gwinnett College, said in a phone interview that he doesn’t believe Abiy’s government has stoked the violence but said that the prime minister has failed to adequately address it: “Ethiopia is becoming more fragile in that, when you look at the federal government’s inability to curb the violence.”

Many experts see the current crisis as the consequence of the Ethiopian government’s decision in the mid-1990s to set up a system of ethnic federalism, giving groups a greater degree of political autonomy within nine ethnic-based regional states. The system was meant to quell conflict in a country with nearly 80 ethnic groups. The problem, as Gedamu put it, is that “you cannot give every ethnic group its own state, so you have to somehow make it work. The political parties have also become ethnic in nature. It led to the growth of so many nationalist movements. Every political and economic grievance is voiced by ethnic parties or movements.”

Jan Egeland, the secretary general of the Norwegian Refugee Council (and former Norwegian foreign minister), who spoke to me by phone from Addis Ababa last week, compared the nation’s problems to those of the former Yugoslavia, saying, “There are many examples of transitions from one social, political system to another, where you see old conflicts popping up. The lid was taken off some of these simmering ethnic conflicts, and some people went completely on a rampage against each other. People started to attack their neighbors after decades of peaceful coexistence.”

Egeland described dire conditions in a refugee camp he had recently visited in the Gedeo region, to which many of those displaced have fled. “There were 16 latrines for 3,500 people in this cramped old factory building. There were torrential rains, so mud and dirt were flowing in,” he said. The government has encouraged people to return to neighboring Oromia, but many are afraid of continued violence.

In addition to its own displaced population, Ethiopia also hosts one of the world’s largest populations of foreign refugees—mainly from Somalia, Eritrea, and Sudan. Ethiopia’s booming economy and relative political stability mean the issues there are critical, not just for its own population but for the surrounding region.

The international displacement crisis has resulted from a collective global failure to both prevent new conflicts from breaking out and to address the lingering effects of old ones. Ethiopia, a country that has made impressive and undeniable progress on so many fronts in recent months, shows just how difficult these conflicts—at once long in the making and suddenly bloody—can be to resolve, and how easily they can worsen.