Dear US presidential candidates, we know you have a fair amount on your respective plates right now, but we'd like to voice some thoughts on science that we hope you will take into your presidency.

As the avid readers of Nature Medicine we presume you to be, you will be aware of some of the key issues we support: financing the US National Institutes of Health (NIH) to ensure long-term consistent growth of the NIH budget and expanded support of biomedical research; reforming the US Food and Drug Administration (FDA) to restore both its efficacy in doing its job and its independence from the perceived influence of big pharma; reinstating the position of the Assistant to the President for Science and Technology to facilitate sound—not ideology-driven—science decisions; and federally funding embryonic stem cell research and establishing regulation for its oversight to enable its future contribution to disease cures and regenerative medicine.

Addressing these issues in the next presidency will both reinvigorate science in the US and strengthen public confidence in biomedical research. But US science funding and policy decisions don't affect the scientific enterprise alone—they influence the physical health of American taxpayers and the financial health of the US as a whole. And, like perturbations in the US economy, changes to US science are felt worldwide. Because of this, decisions on science must take into account both national and international needs and the global consequences of action—or inaction.

As presidential candidates you have been asked your views on a number of science topics, including climate change, research, technology and healthcare. But in today's world, these issues cannot be viewed as separate concerns with independent solutions.

For instance, global warming is not just associated with climate change: higher incidence of mosquito-borne diseases, and increased asthma and respiratory problems due to elevated pollen and mold counts, coupled with the rise in air pollution, can all be linked to global warming. In legislating new CO2 emission standards and supporting the development of alternative energy sources, you must consider the effect of such policies on human health. The US needs to complement new energy initiatives with funding for research efforts to prevent and medical initiatives to treat the healthcare problems that will increase in the interim—both in the US and abroad. Securing the cooperation of the world's largest emitters of greenhouse gases will be essential to effect any real change in CO2 levels and in human health.

Our capability to rapidly traverse the globe facilitates the equally rapid spread of infectious disease, as occurred with SARS, and as is feared of an influenza pandemic. Investment in efforts to detect and control the national spread of infectious disease is important. Ensuring that disease is also contained globally—through provision of drugs, vaccines and medical infrastructure—will help developing nations strengthen their healthcare systems and their ability to respond to outbreaks and ameliorate the conditions that can foster civil unrest.

Yet the benefits to the international community are not limited to the US's efforts in combating infectious diseases such as influenza, malaria and HIV/AIDS. The US commitment to science—in the form of basic and applied research on cancer, diabetes and cardiovascular disease, among others—and the resulting medical advances are both national and international assets. And although financing international aid—directly or indirectly—may not be an election-winning strategy, it is nevertheless a global necessity. But the longer the funding of the NIH remains stagnant, the FDA is beholden to the pharmaceutical industry and science takes a back seat to politics, the longer the US contribution to the study of these diseases and the development of their cures will founder.

Science initiatives cost money. Doubling the funding of the NIH, of cancer and AIDS research and of US aid for world health are crucial first steps (see page 1000) of a process that must be viewed as ongoing. Yet money alone will not provide a panacea for global health. Instead, policies are needed that recognize and address the dependence of the nation's future on science, as well as the inextricably linked needs of the international community, that anticipate future health concerns and that ensure that science and technology can offer both proactive and reactive solutions.

In biology, a systems approach looks at individual players within their larger biological context to understand the far-reaching effects of perturbing the system by changing a single component. We hope that whoever becomes the future president recognizes that US science decisions exist within an international framework and, as such, have both the power to harm and the power to heal.