If it feels like there have been more and more outbreaks of strange, viral diseases in recent years, it’s not just you. Like K-pop, Brexit, and the presidency of Donald Trump, the increased frequency of pandemics is one of the unforeseen results of globalization.

That’s why the 2014 Ebola episode was so much more lethal—more than 11,000 deaths, versus an old high of 280—than the next largest known outbreak. People can move much faster and much farther than they once did, moving viruses around the globe. Meanwhile, expanded human footprints and climate change are bringing humans into more contact with animals.

“As we move into where they live, the risk of exposure gets higher,” said Nancy Sullivan, a senior investigator at the National Institutes of Health, who developed the first Ebola vaccine. Animals have been a factor in pandemics like MERS, SARS, chikungunya, and Zika, in addition to Ebola, she explained Thursday during a discussion at the Aspen Ideas Festival, which is co-hosted by the Aspen Institute and The Atlantic.

But if globalization is a central cause of many epidemics and pandemics, it’s also the only way to solve the problem, said Ron Klain, who was tapped by then-President Barack Obama to head the U.S. response to the 2014 Ebola epidemic. Klain said that episode gave some essential intimations about how public-health officials need to be ready—while doctors and scientists like Sullivan work to find vaccines and treatments.

More than anything, that means increasing capacity for major response.

“I used to say during the Ebola response that people were afraid that people in black helicopters would come and take over the things,” Klain said, referring to the common conspiracy-theory trope. “The thing we needed to be afraid of was that there were no people in black helicopters.”

In other words, containing an epidemic requires a great deal of manpower, and it requires a secure environment. Nongovernmental organizations working in West Africa during the epidemic, amid understandable panic and confusion, became worried that their employees were unsafe—never mind at risk for infection. During the epidemic, Obama for the first time authorized sending U.S. troops to assist in an epidemic response, as did other countries, but that only worked because of existing relationships.

“There are large parts of the world where U.S. troops would not be welcome,” Klain said. As a result, he said, the world needs a UN-style force of international epidemic responders who could go around the world without the baggage of any country’s flag. The World Health Organization, while popularly viewed as this sort of force, is in fact largely a statistical and informational group, with little to no responsive capacity. (UN forces have themselves sometimes helped spread disease in disaster areas.)

The problem isn’t just manpower. There’s also a lattice of legal and regulatory issues that can handcuff epidemic response across national borders. Doses of H1N1 vaccine sat unused during a 2009 outbreak because of questions over drug approval. Intellectual property and legal liability similarly complicate efficient response.

But Klain said there’s much the U.S. can be doing inside its borders as well—starting with formalizing the position he held during the Ebola outbreak. “There should never be someone like me ever again,” he said. “We should have a permanent coordinating capacity in the White House.”

The Stafford Act, which authorizes the president to send aid after natural disasters, doesn’t cover disease outbreaks. And local responders don’t always have all the tools they need. At the start of the Ebola outbreak, Klain said, there were just six hospital beds in the United States capable of treating a patient with a virus like Ebola. By the time the outbreak was contained, that was up to 100—a vast increase by percentage, but far short of what would be needed in a real U.S. epidemic.

But Klain said the temptation to think of quarantines as a solution was a dangerous once. Responders need to be ready for pandemics, rather than to hope they just won’t happen.

“There is no wall we can build, physical or metaphorical, that can protect the people of the United States from pandemics,” he said.