On May 4, world leaders gathered for a virtual vaccine summit.

Most of America's allies took part in the donor event organized by the European Union. Some nongovernmental organizations participated, too, including the Bill and Melinda Gates Foundation. Overall, about $8 billion — and a sense of solidarity — was raised.

The United States was a no-show.

It is true, as Trump administration officials stressed in an off-the-record briefing with Washington reporters (which is telling in itself), that America is a significant and generous contributor to global health efforts (until it is not, as seen in the decision to suspend World Health Organization funding). But it is counterproductive, from a health and geopolitical perspective, that the U.S. has abdicated its global leadership position on the most significant crisis since World War II.

"The more we pull together and share our expertise, the faster our scientists will succeed," said British Prime Minister Boris Johnson, channeling the can-do spirit of the summit.

Pulling together is key to accelerate vaccine development that can saves lives, and livelihoods, worldwide. "Almost every major advance that the scientific community has made in a number of areas, not just COVID-19, has relied on international collaboration — it's so critically important," Dr. Timothy Schacker, vice dean for research at the medical school at the University of Minnesota, told an editorial writer.

"That position of keeping the United States away from that kind of collaboration is likely to impede the speed in which things can get done," Schacker said. "The best idea could emerge from anywhere in the world, but it's going to take a lot of countries to take that idea forward."

This collection of countries has historically been led by the U.S. through military, diplomatic, economic or medical responses to transnational challenges, including health crises like Ebola and AIDS. But the Trump administration has consistently conceded this leadership to others, and even questioned some of the very alliances and international institutions America helped develop — often to the country's great benefit — in the postwar era.

The administration's stance "reinforces the perception that the United States is not interested in working with others to tackle global challenges," Richard Haass, president of the Council of Foreign Relations, told an editorial writer. Haass, a former diplomat who is the author of "The World: A Brief Introduction," among other books about foreign policy, added that the administration's stance has potential health ramifications, too. "It probably slows down the search for a potential vaccine because there is not the pooling of resources that there could or should be," Haas said. "And if it turns out an effective vaccine were to emerge from this effort it disadvantages the U.S. because others would claim they deserve to take care of their citizens first."

A vaccine, by definition, is preventive. One is needed, of course, for the virus. But there's also a need for a geopolitical vaccine to prevent a loss of international coordination and common purpose. It's not too late for President Donald Trump to rise to the gravity of the crisis and position the country to provide leadership in both pursuits.