The U.S. departure from the World Health Organization became official in late January 2026, according to the Trump administration – a year after President Donald Trump signed an executive order on inauguration day of his second term declaring that he was doing so. He first stated his intention to do so during his first term in 2020, early in the COVID-19 pandemic.

The U.S. severing its ties with the WHO will cause ripple effects that linger for years to come, with widespread implications for public health. The Conversation asked Jordan Miller, a public health professor at Arizona State University, to explain what the U.S. departure means in the short and long term.

Why is the US leaving the WHO?

The Trump administration says it’s unfair that the U.S. contributes more than other nations and cites this as the main reason for leaving. The White House’s official announcement gives the example of China, which – despite having a population three times the size of the U.S. – contributes 90% less than the U.S. does to the WHO.

The Trump administration has also claimed that the WHO’s response to the COVID-19 pandemic was botched and that it lacked accountability and transparency.

The WHO has pushed back on these claims, defending its pandemic response, which recommended masking and physical distancing.

The U.S. does provide a disproportionate amount of funding to the WHO. In 2023, for example, U.S. contributions almost tripled that of the European Commission’s and were roughly 50% more than the second highest donor, Germany. But health experts point out that preventing and responding quickly to public health challenges is far less expensive than dealing with those problems once they’ve taken root and spread.

However, the withdrawal process is complicated, despite the U.S. assertion that it is final. Most countries do not have the ability to withdraw, as that is the way the original agreement to join the WHO was designed. But the U.S. inserted a clause into its agreement with the WHO when it agreed to join, stipulating that the U.S. would have the ability to withdraw, as long as it provided a one-year notice and paid all remaining dues. Though the U.S. gave its notice when Trump took office a year ago, it still owes the WHO about US$260 million in fees for 2024-25. There are complicated questions of international law that remain.

What does US withdrawal from the WHO mean in the short term?

In short, the U.S. withdrawal weakens public health abroad and at home. The WHO’s priorities include stopping the spread of infectious diseases, stemming antimicrobial resistance, mitigating natural disasters, providing medication and health services to those who need it, and even preventing chronic diseases. So public health challenges, such as infectious diseases, have to be approached at scale because experience shows that coordination across borders is important for success.

The U.S. has been the largest single funder of the WHO, with contributions in the hundreds of millions of dollars annually over the past decade, so its withdrawal will have immediate operational impacts, limiting the WHO’s ability to continue established programs.

As a result of losing such a significant share of its funding, the WHO announced in a recent memo to staff that it plans to cut roughly 2,300 jobs – a quarter of its workforce – by summer 2026. It also plans to downsize 10 of its divisions to four.

In addition to a long history of funding, U.S. experts have worked closely with the WHO to address public health challenges. Successes stemming from this partnership include effectively responding to several Ebola outbreaks, addressing mpox around the world and the Marburg virus outbreak in Rwanda and Ethiopia. Both the Marburg and Ebola viruses have a 50% fatality rate, on average, so containing these diseases before they reached pandemic-level spread was critically important.

The Infectious Diseases Society of America issued a statement in January 2026 describing the move as “a shortsighted and misguided abandonment of our global health commitments,” noting that “global cooperation and communication are critical to keep our own citizens protected because germs do not respect borders.”

What are the longer-term impacts of US withdrawal?

By withdrawing from the WHO, the U.S. will no longer participate in the organization’s Global Influenza Surveillance and Response System, which has been in operation since 1952. This will seriously compromise the U.S.’s ability to plan and manufacture vaccines to match the predicted flu strains for each coming year.

Annual flu vaccines for the U.S. and globally are developed a year in advance using data that is collected around the world and then analyzed by an international team of experts to predict which strains are likely to be most widespread in the next year. The WHO convenes expert panels twice per year and then makes recommendations on which flu strains to include in each year’s vaccine manufacturing formulation.

While manufacturers will likely still be able to obtain information regarding the WHO’s conclusions, the U.S. will not contribute data in the same way, and American experts will no longer have a role in the process of data analysis. This could lead to problematic differences between WHO recommendations and those coming from U.S. authorities.

The Centers for Disease Control and Prevention estimates that each year in the U.S. millions of people get the flu, hundreds of thousands of Americans are hospitalized and tens of thousands die as a result of influenza. Diminishing the country’s ability to prepare in advance through flu shots will likely mean more hospitalizations and more deaths as a result of the flu.

This is just one example of many of how the U.S.’s departure will affect the country’s readiness to respond to disease threats.

Additionally, the reputational damage done by the U.S. departure cannot be overstated. The U.S. has developed its position as an international leader in public health over many decades as the largest developer and implementer of global health programs.

I believe surrendering this position will diminish the United States’ ability to influence public health strategies internationally, and that is important because global health affects health in the U.S. It will also make it harder to shape a multinational response in the event of another public health crisis like the COVID-19 pandemic.

Public health and policy experts predict that China will use this opportunity to strengthen its position and its global influence, stepping into the power vacuum the U.S. creates by withdrawing. China has pledged an additional US$500 million in support of the WHO over the next five years.

As a member of the WHO, the United States has had ready access to a vast amount of data collected by the WHO and its members. While most data the WHO obtains is ultimately made available to the public, member nations have greater access to detailed information about collection methods and gain access sooner, as new threats are emerging.

Delays in access to data could hamstring the country’s ability to respond in the event of the next infectious disease outbreak.

Could the US return under a new president?

In short, yes. The WHO has clearly signaled its desire to continue to engage with the U.S., saying it “regrets the U.S. decision to withdraw” and hopes the U.S. will reconsider its decision to leave.

In the meantime, individual states have the opportunity to participate. In late January, California announced it will join the WHO’s Global Outbreak Alert & Response Network, which is open to a broader array of participants than just WHO member nations. California was also a founding member of the West Coast Health Alliance, which now includes 14 U.S. states that have agreed to work together to address public health challenges.

California Gov. Gavin Newsom has also launched an initiative designed to improve public health infrastructure and build trust. He enlisted national public health leaders for this effort, including former Centers for Disease Control and Prevention leaders Susan Monarez and Deb Houry, as well as Katelyn Jetelina, who became well known as Your Local Epidemiologist during the COVID-19 pandemic.

I think we will continue to see innovative efforts like these emerging, as political and public health leaders work to fill the vacuum being created by the Trump administration’s disinvestment in public health.

Jordan Miller, Teaching Professor of Public Health, Arizona State University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

When Apollo 13 looped around the Moon in April 1970, more than 40 million people around the world watched the United States recover from a potential catastrophe. An oxygen tank explosion turned a planned landing into an urgent exercise in problem-solving, and the three astronauts on board used the Moon’s gravity to sling themselves safely home. It was a moment of extraordinary human drama, and a revealing geopolitical one.

The Cold War space race was a two-player contest. The Soviet Union and the United States operated in parallel, rarely cooperating, but clearly measuring themselves against one another. By 1970, the United States had already landed on the Moon, and competition centered on demonstrating technological capability, political and economic superiority and national prestige. As Apollo 13 showed, even missions that did not go as planned could reinforce a country’s leadership if they were managed effectively.

More than half a century later, NASA’s Artemis II mission will send humans around the Moon again in early 2026, this time deliberately. But the strategy going into Artemis II looks very different from that of 1970. The United States is no longer competing against a single rival in a largely symbolic race.

As a professor of air and space law, I research questions of governance and conflict avoidance beyond Earth. From a space law perspective, sustained human activity on the Moon and beyond depends on shared expectations about safety and responsible behavior. In practice, the countries that show up, operate repeatedly and demonstrate how activity on the lunar surface and in outer space can be carried out over time shape these expectations.

Artemis II matters not as nostalgia or merely a technical test flight. It is a strategic signal that the United States intends to compete in a different kind of Moon race, one defined less by singular achievements and more by sustained presence, partnerships and the ability to shape how activity on the Moon is conducted.

From a 2-player race to a crowded field

Today, more countries are competing to land on the Moon than ever before, with China emerging as a pacing competitor. While national prestige remains a factor, the stakes now extend well beyond flags and firsts.

Governments remain central actors in the race to the Moon, but they no longer operate alone. Commercial companies design and operate spacecraft, and international partnerships shape missions from the start.

China, in particular, has developed a lunar program that is deliberate, well-resourced and focused on establishing a long-term presence, including plans for a research station. Its robotic missions have landed on the Moon’s far side and returned samples to Earth, and Beijing has announced plans for a crewed landing by 2030. Together, these steps reflect a program built on incremental capability rather than symbolic milestones.

Why Artemis II matters without landing

Artemis II, scheduled to launch in February 2026, will not land on the Moon. Its four-person crew will loop around the Moon’s far side, test life-support and navigation systems, and return to Earth. This mission may appear modest. Strategically, however, crewed missions carry a different weight than robotic missions.

Sending people beyond low Earth orbit requires sustained political commitment to spaceflight, funding stability and systems reliable enough that sovereign and commercial partners can align their own plans around them.

Artemis II also serves as a bridge to Artemis III, the mission where NASA plans to land astronauts near the Moon’s south pole, currently targeted for 2028. A credible, near-term human return signals that the U.S. is moving beyond experimentation and toward a sustained presence.

2 different models for going back to the Moon

The contrast between U.S. and Chinese lunar strategies is increasingly clear.

China’s program is centrally directed and tightly controlled by the state. Its partnerships are selective, and it has released few details about how activities on the Moon would be coordinated with other countries or commercial actors.

The U.S. approach, by contrast, is intentionally open. The Artemis program is designed so partners, both other countries and companies, can operate within a shared framework for exploration, resource use and surface activity.

This openness reflects a strategic choice. Coalitions among countries and companies expand their capabilities and shape expectations about how activities such as landing, operating surface equipment and using local resources are conducted.

When vague rules start to matter

International space law already contains a framework relevant to this emerging competition. Article IX of the 1967 outer space treaty requires countries to conduct their activities with “due regard” for the interests of others and to avoid harmful interference. In simple terms, this means countries are expected to avoid actions that would disrupt or impede the activities of others.

For decades, this obligation remained largely theoretical. On Earth, however, similarly open-ended rules, particularly in maritime contexts, created international conflicts as traffic on shipping lanes, resource extraction and military activity increased. Disputes intensified as some states asserted claims that extended beyond what international law recognized.

The Moon is now approaching a comparable phase.

As more actors converge on resource-rich regions, particularly near the lunar south pole, due regard becomes an immediate operational question rather than a theoretical future issue. How it is interpreted – whether it means simply staying out of each other’s way or actively coordinating activities – will shape who can operate where, and under what conditions.

Washington is naming the race − without panic

During his second Senate Commerce Committee confirmation hearing, NASA Administrator Jared Isaacman was asked directly about competition with China in lunar exploration. He emphasized the importance of keeping U.S. space efforts on track over time, linking the success of the Artemis program to long-term American leadership in space.

A similar perspective appears in a recent U.S. government assessment, the U.S.-China Economic and Security Review Commission’s 2025 annual report to Congress. Chapter 7 addresses space as a domain of strategic competition, highlighting China’s growing capabilities. The report frames human spaceflight and deep-space infrastructure – including spacecraft, lunar bases and supporting technologies – as part of broader strategic efforts. It emphasizes growing a human space program over time, rather than changing course in response to individual setbacks or the accomplishments of other countries.

Recent U.S. policy reflects this emphasis on continuity. A new executive order affirms federal support for sustained lunar operations, as well as commercial participation and coordination across agencies. Rather than treating the Moon as a short-term challenge, the order anticipates long-term activity where clear rules, partnerships and predictability matter.

Artemis II aligns with this posture as one step in the U.S.’s plans for sustained activity on the Moon.

A different kind of test

As Artemis II heads toward the Moon, China will also continue to advance its lunar ambitions, and competition will shape the pace and manner of activity around the Moon. But competition alone does not determine leadership. In my view, leadership emerges when a country demonstrates that its approach reduces uncertainty, supports cooperation and translates ambition into a set of stable operating practices.

Artemis II will not settle the future of the Moon. It does, however, illustrate the American model of space activity built on coalitions, transparency and shared expectations. If sustained, that model could influence how the next era of lunar, and eventually Martian, exploration unfolds.

Michelle L.D. Hanlon, Professor of Air and Space Law, University of Mississippi

This article is republished from The Conversation under a Creative Commons license. Read the original article.