South Africa is the first country where COVID-19 has contributed to serious social disorder (if you don’t count the United States). One of Africa’s wealthiest nations is beset by inequality, corruption, political strife and now a health system that is, in the description of President Cyril Ramaphosa, “buckling” under the strain of Africa’s third COVID wave.

While COVID in South Africa is encouraging disruption, disruption is also encouraging COVID. The government has been forced to close some vaccination sites due to riots and violence (in a country where only about 6% of people have gotten even one jab). The crisis is also interfering with the treatment of other diseases such as tuberculosis and AIDS. Hospitals are reenacting the United States’ worst medical nightmares from last year. Patients are dying while waiting for admittance. “It’s devastating, it’s soul destroying,” one Johannesburg doctor has said. “We are trained to save lives, but you revert to that wartime mentality. You revert to becoming numbed, you revert to becoming blunted.”

Sixteen African countries so far are seeing the deadly result when the delta variant encounters a largely unvaccinated public. Across the continent, the overall vaccination rate is about 2%. Infections are rising 25% each week, causing the World Health Organization’s regional director for Africa to warn that “the speed and scale of Africa’s third wave is like nothing we have seen before.” In Tunisia, the health ministry says its health system has “collapsed.” In Uganda, hospitals are turning away COVID patients for lack of space. In Zimbabwe, there has been a five-fold increase in infections in just two weeks. Almost all of the affected countries need oxygen, field hospitals, testing capacity and more health workers.

Exact figures on the human cost of the crisis are hard to come by, given the lack of testing and difficulties of data collection. The Economist estimates that the true death toll in Africa may be more than 1.4 million, which is more than 10 times the official figure.This much is clear: In the absence of timely, outside help, hundreds of thousands — or more — may die.

And yet there is still no comprehensive plan to mobilize the resources, capabilities and vaccine doses necessary to reach global herd immunity. This is because no world leader has risen to the moment. German Chancellor Angela Merkel is (gracefully) leaving the stage. French President Emmanuel Macron is facing an election. And this leaves President Joe Biden.

This emergency is testing the Biden administration in ways that go beyond global health. The president has mended alliances, rejoined multilateral institutions and returned to the language of democratic internationalism. All good and necessary things. But his largest foreign policy decision has been to abandon Afghanistan to likely conquest and to condemn that nation’s people to brutal oppression. It is not my purpose to revisit this issue (though it deserves revisiting). It is only to point out that Biden’s first great foreign policy decision was a signal of retreat and indifference to human rights. This was hardly reassuring to friends who increasingly doubt not just America’s willingness but also America’s capacity to lead.

The global COVID crisis is a chance, within the boundaries of Biden’s foreign policy vision, to show that the United States is still capable of international leadership, vast ambition and moral purpose. The last time the world faced a similar challenge — during the height of the global AIDS crisis — Biden was one of President George W. Bush’s main congressional partners in passing the President’s Emergency Plan for AIDS Relief (still the largest initiative to fight a single disease in history). In 2003, Biden was on the side of the angels. They are calling again.

So far, the Biden administration has pledged to donate 580 million vaccine doses to the global fight against COVID. Other Group of Seven countries have promised 500 million doses. That leaves us about 10 billion doses short. When the history of the COVID crisis is written, someone will need to explain why, even at this late date, less than 1% of COVID-19 doses globally have been administered to people in low-income countries. It is an abdication for the ages.

The upsides of providing leadership on COVID would be considerable. The downsides of failing to lead are worse. Many lives will be needlessly lost. The risk of new variants will increase. China will step into the leadership gap (as it is already beginning to do). And the world will see dismasted democracies, unable to navigate in this global storm.

The need here is not just material. This effort requires more than generous donors; it needs a coordinator, a quarterback. It needs someone to work with countries on their own mass-vaccination plans — someone who can help provide doses, supplies, equipment and on-the-ground expertise. Only America has done this kind of thing before. Only America can do it again.

Michael Gerson’s email address is michaelgerson@washpost.com.