Four years after a war that killed hundreds of thousands of people in Ethiopia’s northernmost region, the graves had barely settled when the calendar began to repeat itself. Between 2020 and 2022 the armies of Ethiopia and Eritrea fought the Tigray People’s Liberation Front until exhaustion stopped them. The abuses were grave enough that in 2021 America imposed an arms embargo on Ethiopia and sanctions on Eritrea’s army, its senior officials and its state-owned conglomerates. On September 18th the United States lifted the embargo and let the sanctions lapse. “The national emergency [in Ethiopia] has expired,” the Treasury Department declared, in the confidence with which distant capitals close files.

Five days later the file blew open. On September 23rd forces loyal to the TPLF seized control of three airports in Tigray, and Ethiopia’s federal government suspended flights to the region. The TPLF accused the Ethiopian army of attacking southern Tigray and announced its forces had “entered a defensive war.” An Ethiopian official answered that the TPLF had in fact “launched an all-out offensive” against army positions in the neighbouring regions of Amhara and Afar. At the time of the Economist’s report, heavy fighting appeared to be under way in both regions as well as in southern Tigray.

The alliance of seven

The quarrel had been rehearsing for more than a year. The TPLF accused Prime Minister Abiy Ahmed of holding Tigray under a punitive siege, part of what it called a “genocidal” campaign; Abiy’s government called the TPLF a “Trojan horse” for hostile forces bent on dismantling Ethiopia, first among them Eritrea. In recent weeks the Ethiopian army had been waging an undeclared drone war against Tigrayan positions. Then, on September 20th — the geometry of enemies and friends having rotated once more — the TPLF and the Fano militias of Amhara, who had fought each other bloodily in the last war, signed a statement with five other rebel groups announcing an alliance to topple Abiy’s regime, a pact we have described in detail.

Eritrean officials deny any part in the coalition. But Isaias Afwerki, Eritrea’s 80-year-old dictator, nursed his own grievances: he had felt betrayed when Abiy made peace with the TPLF in 2022, and he has grown alarmed at Abiy’s repeated threats to annex part of Eritrea’s coastline. He has longstanding ties to the Fano, and is understood to have supplied the TPLF and other groups with weapons and logistical support. That both Eritrean troops and the Fano fought alongside Abiy against the TPLF last time, and are now quietly on the other side — the Fano rose in open rebellion against the federal government in 2023 — says everything about the loyalty of pacts in this corner of Africa.

The road to the capital

The militaries have already drawn their geometry on the map. The TPLF and the Fano appear to be trying to encircle Weldiya, a town in northern Amhara that sits on the main road linking Tigray with Addis Ababa; if Weldiya falls, the way toward an offensive on the capital could open. The rebels have also pushed into Afar, where the road to the port of Djibouti runs — the artery along which Ethiopia receives nearly all of its international trade, including its fuel. “The war has already started,” a former Ethiopian intelligence officer told The Economist.

Abiy holds two cards. The first is the rebels themselves: individually weak, collectively riven by ethnic rivalries and old grievances, perhaps unable to co-ordinate. The second is the sky. In 2021, when the TPLF last drove toward the capital, the Ethiopian army beat it back with drones; today the arsenal is larger and more sophisticated. In May one of the prime minister’s advisers called for the TPLF’s leaders to be assassinated in targeted drone strikes. “The TPLF leadership may not last the week,” a well-connected observer predicted.

The neighbours at the door

Yet a fire in an old wooden neighbourhood does not respect fences. Should Ethiopia’s rebels falter, Isaias may conclude he is next on the menu and order his troops into the fight. And Eritrea is a crucial ally of the Sudanese Armed Forces, the national army locked in Sudan’s own catastrophic civil war; the SAF, in turn, is furious with Ethiopia for backing its enemy, the Rapid Support Forces. The arithmetic of vengeance connects Addis Ababa to Asmara to Khartoum. “It’s not going to be confined to Tigray,” a TPLF official predicted. “It’s going to involve Eritrea and it’s going to involve Sudan.” It is an old lesson of this region that wars are easier to start than Embassies are to reopen — and easier to widen than to bury.