Only America Can Prevent a New War in the Horn of Africa

Mulugeta Gebrehiwot Berhe and Alex de Waa

FOREIGN AFFAIRS

Over the past 20 months, as multiple wars have swept across the Middle East, the southern end of the Red Sea has become a source of international concern. In the early months of 2025 alone, the United States spent billions of dollars on a high-profile military campaign against the Houthis in Yemen, who have continued to attack international shipping in this crucial body of water in response to Israel’s war in Gaza. Yet regional and world powers have largely ignored a volatile crisis on the Red Sea’s other coast, along the Horn of Africa, that could soon erupt into a major conflagration.

The crisis involves the coastal nation of Eritrea and its larger landlocked neighbor Ethiopia, which lost access to the Red Sea after Eritrean independence in 1993. In November 2023, Ethiopian Prime Minister Abiy Ahmed said that gaining Red Sea access has become an existential question for Ethiopia. In particular, he claims that Ethiopia should control Assab, a crucial port in southern Eritrea. Since then, tensions between the two countries have mounted, and Ethiopia may be preparing to march its forces directly to Assab, which is only 37 miles from the Ethiopian border. Although Abiy has denied that Ethiopia has plans for a military conflict, both sides have been buying military equipment, including armed drones, drone defenses, missiles, mechanized firepower, and desert terrain armored vehicles. In recent weeks, both have also moved military forces to the border near Assab and are engaging in escalating exchanges of hostile rhetoric.

A battle over the Red Sea port would be dangerous. But what makes the looming conflict even more threatening is the likelihood that it could quickly spread to Ethiopia’s volatile Tigray region, which borders Eritrea and which was the epicenter of a devastating 2020–22 war between the Ethiopian federal government in Addis Ababa and the Tigray People’s Liberation Front. In the aftermath of that war—which cost as many as 600,000 lives, including hundreds of thousands of civilians, and left a dismal legacy of displacement and destruction—a peace agreement was supposed to bring new stability to the region. But since then, few of the agreement’s provisions have been implemented. Eritrean troops are still present in the region and large parts of Tigray have been de facto annexed by Ethiopia’s neighboring Amhara region. More than one million Tigrayans remain unable to return home. Most worrying of all, the leadership of the TPLF has split into contending factions, which are forging rival alliances with Ethiopia and Eritrea and building separate armed wings.

If fighting breaks out between Ethiopia and Eritrea, Tigray will again be the main battleground, with potentially catastrophic consequences—for Tigray and for the entire Horn of Africa. Both sides have large, well-equipped armies and are prepared to inflict and absorb casualties on a vast scale. A conflict would tear up what remains of a fragile peace and security architecture in the region, and could draw in Somalia and Sudan in a region-wide vortex of violence. Further fueling instability is the rival meddling of leading Middle Eastern powers, with the United Arab Emirates supporting Ethiopia, and Egypt, Saudi Arabia, and Turkey leaning toward Eritrea.

A new war can be prevented. With the right kind of international pressure, the government of Ethiopia could be pushed to enforce the 2022 peace agreement, a long-standing demand of the Tigrayans. Tigrayan leaders themselves must also take steps to avoid becoming pawns of a larger Ethiopian-Eritrean fight. Indeed, if Tigray stays neutral, it would be difficult for Abiy to mount an attack on the port of Assab alone. In previous decades, the prospect of a major war in the Horn would have mobilized diplomats in Washington, in European capitals, and at the United Nations, as well as the African Union. Today, Western leaders are distracted and multinational organizations are weakened. The only actor with the leverage to bring the multiple actors to the table is the United States.

GRUDGE MATCH

Tigray’s pivotal role in the tensions between Ethiopia and Eritrea goes back to the aftermath of the Tigrayan war. When the war began, Ethiopia and Eritrea were on the same side, combining forces to try to defeat the Tigrayan People’s Liberation Front. Abiy sought to impose his will on the TPLF, which had refused to dissolve and integrate into his new ruling party in Addis Ababa. In turn, Eritrean president Isaias Afwerki had long held a grudge against the TPLF and was determined not only to dismantle it but also to inflict so much damage on Tigray that the region’s forces could never challenge Eritrea again. The two leaders enlisted militia from Ethiopia’s neighboring Amhara region, who had their own reasons for joining the conflict, seeking to annex parts of Tigray that they claimed as historically Amhara land.

After two years of intense fighting, including a starvation siege that plunged Tigray into famine, the Tigrayans sued for peace. The United States brought the Ethiopian government and the TPLF to the table in Pretoria, South Africa, under the auspices of the African Union, and in November 2022, the two sides signed a permanent cessation of hostilities agreement. But the deal contained several flaws. First, it was hastily contrived and had weak monitoring and enforcement mechanisms. Despite claiming the Pretoria Agreement as a diplomatic triumph, the United States did little to enforce it. Both sides mostly ignored the provisions of the deal, and even basic humanitarian assistance needs for Tigray went unmet.

Worse, the Pretoria negotiations had failed to include Eritrea and the Amhara leaders—the other major parties to the conflict. The mediators had worked on the assumption that both would follow Abiy’s lead. Instead, they quickly fell out with him. In early 2023, Abiy ordered the Amhara region to disarm its militia, known as FANO, and to have its special forces downgraded to riot control police. They refused. Within weeks, FANO had launched an insurgency against Ethiopian forces across vast swaths of the Amhara region, which continues today. Every month there are reports of scores, sometimes hundreds, killed in skirmishes, civilian massacres, and drone attacks; the UN has estimated half a million displaced people need urgent assistance.