The two of us have spent nearly every day of the past 17 years working on the fight against disease and poverty, but today, we are concerned. After a generation of historic progress, the world’s commitment to helping its poorest people is more uncertain than at any time since we started our foundation.

President Donald Trump has recommended a cut of some 30% to the State Department’s budget, which includes the funding for the U.S. Agency for International Development and most of America’s investments in global health. Congress is unlikely to go along with such large cuts, but our best guess is that, by the time the dust settles, key foreign-aid programs will be scaled back. Even modest cuts would represent the reversal of a long-term trend of increasing U.S. support for foreign aid, and a similar mood of retrenchment has taken hold elsewhere. In the U.K., the world’s second-largest aid donor, there has been heated public debate about the value of foreign assistance, but the government has held the line on its commitments.

Public-opinion research shows that many Americans want to spend less on foreign aid, and even those in favor of it register soft support. But the research also reveals that most don’t have a clear understanding of what foreign aid is, how much the U.S. spends on it or what it has accomplished.

When our foundation ran focus groups, we asked people to draw pictures of how they thought U.S. foreign aid worked. We got back lots of illustrations of airplanes dropping dollar bills randomly over dystopian landscapes. That may have been an accurate depiction during the Cold War, when foreign aid was used to curry political favor, but it has nothing to do with the work that our foundation and its partners invest in now.

We’ve been advocating for aid for almost two decades, but it turns out that we and those who share our commitment haven’t done a very good job of explaining just what it is we’re advocating for. We’d like to start doing better.

Foreign aid is nothing more than the money that the U.S. spends to help poor countries around the world to improve the lives of their citizens. Disease and poverty are the clearest examples we know of solvable human misery, and the moral case for wiping them out is clear on its face. The lives of millions and the livelihoods of billions depend on the programs that American foreign aid supports.

The practical case is also becoming increasingly obvious. We see repeatedly that when people anywhere are desperate, people everywhere are at risk. In a world where pandemic disease spreads from one continent to another in the span of a few hours, where terrorist attacks are more random and frequent, and where political crises trigger mass migration, it is in our collective interest to fight against the daily reality of poverty, sickness and frustration. Spending a little to keep a child healthy isn’t only a moral imperative; it is also a long-term investment in a secure and thriving world.

The U.S. devotes less than 1% of its annual budget to foreign aid (though there is no single foreign aid budget, so it’s challenging to be precise). According to the Organization for Economic Cooperation and Development, American taxpayers spent $12.8 billion last year on global public health. Total global public health spending from all donor governments was $37.6 billion. Philanthropies like ours also invest in this work, but our spending is dwarfed by that of governments. Last year, our foundation, by far the largest in the world, spent $2.9 billion on global health.

The work of ensuring that the poorest have a chance to lead healthy and productive lives is funded primarily by the governments of developing countries themselves. But the aid supplied by the U.S. government fills crucial gaps that no other funder can fill. Continuing to invest in that aid is vital to the future of our country and the world.

In 2015, the U.N. adopted the Sustainable Development Goals, or SDGs, a set of targets in key categories like health, agriculture and nutrition that all countries pledged to hit by 2030. This week, in conjunction with the Institute for Health Metrics and Evaluation at the University of Washington, we are releasing a report, “Goalkeepers: The Stories Behind the Data,” to highlight some of the most promising approaches to meeting the SDGs.

The report tracks progress on a number of data points that give the clearest picture of the world’s health and well-being. It also tells the stories of the countries that have been most innovative in tackling issues such as family planning (Senegal), financial inclusion (India), maternal mortality (Ethiopia) and stunting (Peru).

In preparing the report, we kept coming back to three observations. First, there is a set of key priorities on which long-term global stability depends. Second, innovative programs have addressed these priorities effectively in countries around the world. Third, U.S. foreign aid has played a catalytic role in helping leaders to implement these successful programs.

You don’t hear much about HIV/AIDS anymore—certainly not as much as you used to. That is because AIDS drugs have turned what used to be a death sentence into a chronic disease, not just in the U.S. but also in the world’s poorest countries. It is easy to forget the mood of crisis around the turn of the millennium, when a Newsweek cover read “10 Million Orphans.”

The global success of the fight against HIV is due to two very effective development programs: the President’s Emergency Plan for AIDS Relief, or PEPFAR, a U.S. program created under President George W. Bush, and the Global Fund to Fight AIDS, Tuberculosis and Malaria, a global program to which the U.S. is a key contributor.

Funding cuts to either PEPFAR or the Global Fund would be deadly. A 10% cut in funding to HIV treatment now would cost the lives of more than five million people by 2030. But cuts won’t just affect treatment. They will also reduce the funds available for HIV prevention, and given population-growth projections, we need to be ramping up HIV prevention programs, not scaling them back.

Consider the demographics of Africa. In 1990, there were 94 million people on the continent between the ages of 15 and 24, the period when people are most at risk of contracting HIV. By 2030, Africa will have more than 280 million people in that age cohort. If we just maintain the current level of success, the absolute number of people getting HIV in Africa will surpass its peak in the early 2000s, when HIV was a globally recognized crisis.

One way to help manage this crisis is investing in family planning, which contributes to the success of virtually every single development goal. Maternal and child survival, education, prosperity—everything improves when women can plan their pregnancies so that they have children only when they are physically and economically ready.

The president’s recent budget recommendation, however, called for the complete elimination of U.S. funding for global family planning programs. Early indications from Congress are that it won’t zero out the budget, but American aid to family planning may be reduced significantly. This would devastate efforts in countries like Senegal, where U.S. aid is supporting the government’s launch of an ambitious national plan to help women take more control of their lives.

In 2011, only 10% of women of reproductive age in Senegal were using modern contraceptives (compared with more than 75% in the U.S.). Part of the problem was extremely low demand. Cultural norms dictated that women have a lot of children, and most people didn’t understand the health risks of frequent pregnancies. It didn’t help that there were also serious problems with supply. Some kinds of contraceptives were out of stock in public-health clinics 80% of the time.

Senegal invested in a massive public-awareness campaign, involving everything from televised debates to training sessions with local imams, to help build demand. It also brought in private sector partners to decentralize its supply chains and reduce stock outages to less than 2% nationally.

In just five years, the percentage of women using modern contraceptives in Senegal went up by more than half. Now that the program is proven to work, the government is in the process of increasing its share of the funding for it—a budgeted 66% increase by 2020—but the loss of U.S. support now could derail the whole effort.

One of the many goals that family planning helps to achieve is reducing stunting. Children who meet the medical definition of “stunted” are short for their age by a specified amount. But it isn’t actually children’s height we’re concerned about. Stunting is a proxy for how children are developing cognitively and physically. Stunted children are unlikely to reach their full potential, and countries with high levels of stunting are less likely to develop economically.

Stunting is complex because it is caused by multiple factors—a mother’s health, a child’s diet, disease history, environment—that accumulate over time. Researchers are still piecing together a complete picture of the root causes, and there is no single intervention to prevent it. Countries have to mix and match a variety of approaches.

Peru has gotten closer than any other country to cracking the problem. In the early 2000s, Peru had pushed into the ranks of middle-income countries but still had the stunting rates of a low-income country (about 30%). Donors were pulling out, but one of the last projects funded by U.S. aid tested the effects of a mixed package of health and nutrition interventions in 1,200 villages. The results were extraordinary.

So extraordinary, in fact, that, with help from local advocates, the Peruvian government decided to entirely reconceive its anti-stunting program based on the evidence from that U.S.-funded initiative. In less than a decade, Peru cut its stunting rate in half. Now the U.S. Agency for International Development is helping millions of children in 19 countries to thrive by contributing to nutrition programs based on the lessons learned in Peru and elsewhere.

The key to delivering basic services like family planning and nutrition counseling is primary health care. Good primary care addresses 90% of people’s health needs. Countries that have put in place good systems, such as Ethiopia, have made amazing advances.

Ethiopia’s Health Extension Program employs 40,000 health workers, almost all of them women, who fan out across the country, reaching all 100 million Ethiopians. As a result, child mortality in Ethiopia fell by more than half in just 10 years. The Health Extension Program is one reason that a country once notorious for famines is now on the path to middle-income status.

Unfortunately, in many developing countries, including such very large ones as the Democratic Republic of the Congo, Nigeria, Pakistan and Yemen, health systems are reaching just a fraction of their people. These countries are also projected to have the fastest population growth, which means that a larger proportion of the world will live where people are the most vulnerable. A stable future will depend on addressing this demographic shift and ensuring that basic health services are available to all.

We have worked in international development for a long time. We started because we believe that what Warren Buffett calls the “ovarian lottery”—the happenstance of where children are born—shouldn’t determine the fate of individuals.

Over time, we’ve learned how the moral argument for foreign aid dovetails with practical ones. The recent outbreaks of Ebola and Zika have showed us that weak health systems and underinvestment in research and development put everyone at risk. If a disease equivalent to the Spanish flu of 1918 were to spread quickly today, as many as 30 million people could die, and the economic impact would be in the trillions of dollars. U.S. investments in global health security help developing countries to prepare so that outbreaks don’t become pandemics, and basic research funded through the National Institutes of Health leads to new drugs and vaccines that can prevent outbreaks from happening in the first place.

Creating more opportunities in poor places also makes the world more peaceful. As Defense Secretary Jim Mattis said when he was a Marine general and led U.S. Central Command, “If you don’t fully fund the State Department, then I need to buy more ammunition.”

Foreign aid isn’t perfect. Like the private sector, the development sector sometimes fails, and we learn from our failures. When we succeed, we still think about how to do more for less, whether the money comes from taxpayers or philanthropic organizations like our own. But U.S. foreign aid is spent purposefully and measured constantly, and on balance, it is extremely effective.

This doesn’t put all debate to rest. The American people still have to decide how much they want to spend and how it should be spent. That is a discussion we look forward to having, once we’re all agreed on what the discussion is really about.

Our country’s modest investment in the well-being of the poorest saves and improves lives, frees up vast amounts of human potential that’s been locked away by disease and poverty, and helps prevent global crises before they happen. Generosity is one of our best exports. We are confident that Americans will want their government to continue making strategic investments in a safer, healthier, more prosperous world.

This story was originally featured on The Wall Street Journal