Could Joe Biden become the first American president to sanction a Nobel Peace Prize winner for war crimes and human-rights abuses? As the U.S. steps up efforts to end Ethiopia’s bloody civil war, it must reckon with credible reports that the government of the 2019 laureate Prime Minister Abiy Ahmed instigated the conflict and covered up gross abuses.

Biden’s envoy for the Horn of Africa, Jeffrey Feltman, was scheduled to arrive in Addis Ababa Thursday to advocate peace talks between the Ethiopian government and rebels in the northern region of Tigray. Now in its second year, the war has claimed thousands of lives and displaced millions. It is in a stalemate, with Abiy at a slight advantage: His federal forces have regained territory lost in early November but are unable to make headway into Tigray. The rebel leadership claims to have made a strategic retreat and has indicated a willingness to hold peace talks.

Abiy has ramped up air strikes, using drones acquired from Turkey and the United Arab Emirates, which have killed scores of Tigrayans. A land offensive would be much bloodier, for both sides. But the prime minister will likely want a thrust deep into Tigray before agreeing to any meaningful parleys. For one thing, this would give him the upper hand in any negotiations. For another, having portrayed himself as a military leader - in the time-honored fashion, he visited the frontlines dressed in fatigues - he needs something that at least looks like a victory.

Feltman’s first order of business should be to restrain Abiy. The prime minister has thus far been immune to persuasion and to punitive economic measures, such as the suspension of European aid and the blocking of duty-free access to the U.S. market. But these, in effect, punish all Ethiopians for the actions of their leaders.

More targeted measures are called for. Biden has threatened to use sanctions to end the fighting, but has only imposed them on the third party to the conflict - the government of neighboring Eritrea, which entered the civil war on Abiy’s side. It is time to call out and sanction Ethiopians, on both the Tigrayan and government sides, who have enabled or committed crimes and abuses.

Despite the hurdles put up by the government, human rights agencies and humanitarian groups have been tabulating offenses by all combatants. Even as officials in Addis Ababa talk up war crimes ascribed to the rebels, they have suppressed information of wrongdoing - including mass rape and the recruitment of child fighters - by government forces and allied militias. Fislan Abdi, the minister Abiy tasked to document abuses, told the Washington Post last week that she was told to sweep inconvenient facts under the carpet. She resigned.

That brings up the question of Abiy’s culpability. His government claims the rebels sparked the civil war when they attacked a military base, but it is now becoming clear that the prime minister had been preparing an assault on the northern region long before then. As the New York Times has reported, Abiy plotted with the Eritrea’s President Isaias Afwerki against the Tigrayans even as the two leaders negotiated an end to decades of enmity between their countries in 2018 - the deal that won Abiy his Nobel.

The prime minister was apparently counting on the Peace Prize to draw attention away from the preparations that he and Isais were making for war against their common enemy: the Tigray People’s Liberation Front. Although the Tigrayans are a minority in multiethnic Ethiopia, the TPLF ran the government for the best part of three decades before Abiy’s accession to power. The Eritreans blame the TPLF for the war between the countries. Abiy is from the Oromo, the largest ethnic group, which was long denied a fair share of power by the Tigrayans.

Since he became prime minister, Abiy has systematically marginalized Tigrayans in the central government. The civil war has provided cover for crimes by government officials and forces. In the most recent example, says Human Rights Watch, thousands of Tigrayans repatriated from Saudi Arabia have been subjected to abuses ranging from arbitrary detention to forcible disappearance.

Abiy is hardly the first Nobel laureate to have brought dishonor to the prize. But, for obvious reasons, American presidents are leery about deploying sanctions against those who have been ennobled as peacemakers.

George W. Bush considered sanctioning Palestinian leader Yasser Arafat, joint winner in 1994, but eventually thought better of it. For all his recklessness, Donald Trump could not bring himself to sanction Myanmar’s Aung San Suu Kyi, winner in 1991, for her government’s gruesome treatment of the Rohingya minority, and targeted only the country’s military commanders. (Ironically, those same commanders would go on to overthrow the civilian government and imprison Suu Kyi.)

Biden might do well to follow Trump’s example and target senior Ethiopian officials while giving Abiy a Nobel pass. Still, if the prime minister doesn’t take heed, he may well find himself in an ignoble category all of his own.

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This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners. Bobby Ghosh is a Bloomberg Opinion columnist.