The U.N. secretary general, Antonio Guterres, and Pope Francis have both called for a cessation of all global conflicts to focus on what Mr. Guterres called “the true fight of our lives.” Last week Saudi Arabia announced a cease-fire in its war against Houthi rebels in Yemen, and armed groups have indicated a desire to stop fighting in Colombia, Cameroon and the Philippines. The Afghan government and the Taliban have both begun efforts to stem the spread of the virus. And Russia may find the burden of supporting Syrian troops or secessionists in eastern Ukraine excessive if Covid-19 begins to take a heavy toll on the economy.

But the Islamic State has called on its followers to ramp up their efforts. The Houthis have not reciprocated Saudi Arabia’s cease-fire, and fighting has escalated in parts of sub-Saharan Africa.

It is understandable that governments of rich nations have focused first and foremost on the crisis within their own borders. Nothing like the coronavirus has ever overwhelmed so much of the world in such short order, or with such cataclysmic force. Yet it is dismaying that a danger that confronts the entire world, that is likely to hurt the entire global economy, has led to so little global cooperation and has been met with so little global leadership.

This is a crisis in which the United States could have emerged as the leader. The country still may do so. But on top of the widely chronicled failures at home, the Trump administration has provided little inspiration for the world. The response in Europe has also been marked by confusion and disunity: The president of the European Union’s main science organization resigned last week in protest of the bloc's handling of the crisis. The World Health Organization, meanwhile, is under heavy fire from critics who say its complicated relationship with China may have undermined its mission.

That is not likely to change, especially while the disease continues to ravage the United States, Italy, Spain and many other countries in the Northern Hemisphere, and most especially in an American presidential election year, when the struggle against Covid-19 is likely to become only more politicized.

But the weakness of Washington should not prevent the brain trust of the developed world — the think tanks, news media, universities and nongovernmental organizations — from focusing on a strategy for the next and possibly most brutal front in the struggle against the scourge of the coronavirus. Many organizations have already begun to do so, recognizing that this may be the defining struggle of our era, and that if ever the world demanded a global response, this is it.

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