During my eight years on the White House National Security Council staff, it was clear that any decision relating to nuclear weapons would be made by President Bill Clinton. Ever since the nuclear attacks ending World War II that together killed or injured more than 200,000, the horrific potential of a single nuclear weapon to decimate defenseless civilian populations had made such decisions inherently presidential.

In my tenure, the president signed more than 20 directives relating to our nuclear stockpile and arms control talks. Most recently, President Joe Biden had to agree to reaffirm the principle that "a nuclear war cannot be won and must never be fought," overcoming four years of resistance to that pledge during the Trump era.

A nuclear weapon, however, is not the only weapon capable of inflicting mass destruction — a lesson we are learning again today in the Tigray region of Ethiopia, where a man-made famine now threatens millions.

Last November, Ethiopian Prime Minister Abiy Ahmed — claiming he was responding to an attack by the region's ruling party, the Tigray People's Liberation Front (TPLF), on a federal army base following a disputed election and aid cutoff from the central government — ordered the Ethiopian military into Tigray, supported by local Amhara militias and Eritrea. The resulting campaign — involving torture, rape, execution, blockades, starvation and ethnic cleansing — has inflicted a human cost in lives rivaling that of a nuclear bomb.

With the Tigray forces now on the offensive, a wider war and devastation awaits. The Ethiopian diaspora in Minnesota, one of the largest in the United States, suffers as family and friends have been cut off from contact, or worse.

The U.S. had no role in starting this ill-conceived war, but only the U.S., working with its allies in the European Union and others with influence in Ethiopia, has the influence and power to bend the parties toward a ceasefire, negotiations and political resolution. And just as anything nuclear is inherently presidential, so is stopping an unfolding genocide. Biden will need to engage.

Whereas presidential responsibility for nuclear use has been clear, presidents have been hesitant to accept the same mantle of authority applied to genocide. When crises have arisen over the past three decades in Yugoslavia, Rwanda and Myanmar, sub-Cabinet and Cabinet officials have typically taken the lead, meeting to debate the facts and the U.S. national interest and to pursue measures that have one thing in common: They do not fundamentally alter the deadly dynamic on the ground until thousands have paid with their lives.

Ethiopia, the second largest country in Africa and an engine for economic growth and prosperity across the continent, is on the verge of a total war with itself, a war that could lead to years of suffering and ultimately the disintegration of the Ethiopian state. Already, tens of thousands have died, 2 million of Tigray's 6 million people reportedly have fled their homes, and famine conditions on a biblical scale have been imposed as a weapon of war.

Biden issued a written statement on Ethiopia in May expressing his deep concern. U.S. Secretary of State Anthony Blinken has consistently called for the Ethiopian government to end the conflict and stop the atrocities, and the appointment of Jeffrey Feltman as U.S. special envoy for the Horn of Africa signaled both concern and commitment. Most recently, United States Agency for International Development Administrator Samantha Power went to Sudan and Ethiopia, putting a welcome spotlight on the plight of suffering civilians (though Abiy refused to meet with her).

Yet if the president doesn't throw his weight behind Washington's efforts, none of this will be enough to change the murderous dynamic unleashed last November when Abiy turned what was still largely a political conflict with the TPLF into a genocidal military conflict. In a fateful run of bad decisions, Abiy has united Tigrayans behind the TPLF and filled their ranks with new supporters, led his own Army to destruction in Tigray, and has ignited ethnic conflicts that threaten Ethiopia's survival.

Without a considerable external influence, it's hard to bet on his making the right choice to sit down with the TPLF, assuming members of that party will sit down with him. Indeed, in the past few weeks, Abiy has used dehumanizing rhetoric — referring to the TPLF as a "cancer" and "invasive weed" — and has threatened to unleash "the entire defensive capability" of Ethiopia against Tigray.

On Tuesday, the prime minister's office issued a chilling statement calling on all Ethiopians to be "the eyes and ears of the country in order to track down and expose spies and agents" of the Tigray forces.

What is lacking is a credible process and mediator — before the unraveling. Sadly, the African Union hasn't the credibility or the capacity to act. The United Nations Security Council has been ineffectual, and China and Russia may be more likely to rearm the Ethiopian military and try to turn it into a winner.

Once again, the United States must lead — and once again, the president will have to make the decision and become personally invested in the effort.

Minnesota's congressional delegation should come together to make this case to the White House, working with other colleagues in Congress who represent this vibrant constituency across the U.S. This is not a military intervention or nation-building exercise. What is required is the proffering of U.S. and international support — from heads of government — for an internal Ethiopian political process where decisions to pull back from military and genocidal acts are incentivized, aid can be delivered unhindered, and a durable political solution can be hammered out.

Ethiopia does not have to devolve into this era's Rwanda, where we look back and ask "What could we have done?" and "Why didn't we?" But that's where we are heading now.

Steve Andreasen was the National Security Council's staff director for defense policy and arms control from 1993 to 2001 and teaches at the Hubert H. Humphrey School of Public Affairs at the University of Minnesota.