If talk of a collapsing “international order” can feel like a distant abstraction, look to the Horn of Africa for a sense of its reality on the ground.

The countries of this region—marked by rugged highlands, rift valleys, and arid coastal plains—have become troubling examples of a new era of global politics, where the strong dominate the weak, the institutions set up to forge peace are constantly failing, and the transactional economic interests of an array of outside powers overshadow the plight of civilians. In Ethiopia, a long-simmering conflict recently exploded into open war.

Over the weekend, government troops and allied fighters pushed back the advances of an alliance of factions that are in rebellion against Prime Minister Abiy Ahmed’s central government.

By Monday, they were in control of Mekelle, the capital of the Tigray region and the seat of the Tigray People’s Liberation Front, which is one of the militias in the coalition that wants to oust Abiy.

Weeks of violence, stretching from Addis Ababa, the capital, to areas in Ethiopia’s north and east, have led to dozens of reported casualties, internet and phone disruptions, and fears of a humanitarian crisis.

Friction between the T.P.L.F., which had once dominated Ethiopian politics, and Abiy’s government underlay a civil war that began in 2020 and saw estimates of as many as six hundred thousand people killed and allegations of war crimes.

An internationally brokered peace in 2022 failed to hold, amid various turf wars, paving the way for fresh trauma.

Powers in the Horn of Africa, the Middle East, and beyond are being drawn toward the conflict, which diplomatic efforts have failed to stop.