Hillary Clinton and Donald Trump are battling for the White House. Credit: Left: Win McNamee/Getty. Right: Win McNamee/Getty

Science is slowly coming into focus in the US presidential campaign. Although neither Republican Donald Trump nor Democrat Hillary Clinton has emphasized core research issues, the candidates — and their parties — are beginning to flesh out their positions on climate change, education, biomedical research and other topics that involve the scientific community.

Trump’s immigration stance stokes fears for science

Trump’s pick of Indiana Governor Mike Pence as his running mate on 15 July signalled a sharp turn towards the Republican party’s conservative base. Pence, a self-described Christian conservative, has questioned the existence of climate change, waffled on evolution and criticized President Barack Obama for supporting embryonic-stem-cell research. His new role aligns with the hard-line policy platform adopted at the Republican convention, where Trump officially became the party’s nominee on 19 July.

If Trump wins, Pence’s rise could embolden conservative Republicans to seek new limits on federal funding for embryonic-stem-cell research. But predicting how Trump would govern is a dangerous parlour game, says Michael Werner, executive director of the Alliance for Regenerative Medicine, an advocacy group in Washington DC: “We really don’t know what a Trump–Pence administration would do.”

It’s a common refrain. Deciphering Trump’s views on core science issues has been difficult given the free-wheeling style of his populist campaign. He has often seemed to focus more on taunting the political establishment than on staking out policy positions. By contrast, the Clinton campaign has consulted dozens of scientists on topics that include health, education and the environment.

“Trump doesn’t have a prominent policy shop and a prominent set of policy advisers,” says Douglas Holtz-Eakin, who counselled Republican senator John McCain (Arizona) on economic policy during his failed 2008 presidential bid. “Clinton has a vast bureaucracy and a ten-point plan for going out to lunch, so they couldn’t be more different.”

US Supreme Court puts Obama climate regulations on hold

The two candidates — whose campaign staff declined multiple interview requests — also seem to think very differently about the role of science. Although Clinton has described science and innovation as a foundation for the future, science funding seems to be an afterthought for Trump, says John Karsten, coordinator of the Center for Technology Innovation at the Brookings Institution, a think tank in Washington DC. Instead, the Republican has focused on issues such as national security, immigration and crumbling infrastructure.

Climate change is one of the few science topics that has grabbed the campaign spotlight — in part because of Republican anger over Obama’s regulations to limit greenhouse-gas emissions from power plants, vehicles and oil and gas development. Clinton’s climate and energy proposals would largely maintain the current course; by contrast, in a major policy speech on 26 May, Trump promised to roll back Obama’s “totalitarian” regulations and withdraw the United States from the Paris climate agreement. Trump, who has long denied mainstream climate science, also said that his administration will focus on “real environmental challenges, not phony ones”.

Split tickets

This yawning philosophical divide is apparent in the party platforms that the Republicans and Democrats developed ahead of their nominating conventions this month. Environmentalists have criticized the Republican platform for labelling coal a “clean” energy source, even though it produces more carbon dioxide emissions per unit of energy than any other fossil fuel. Democrats, meanwhile, are poised to adopt a platform this week at their national convention that calls for using “every tool available to reduce emissions now”.

What do you think of the Presidential candidates?

“Climate is going to be talked about in this campaign, because the candidates have distinctly different positions,” says Michael Oppenheimer, a climate scientist at Princeton University in New Jersey who is advising the Clinton team. Although his workload was light during primary season, Oppenheimer anticipates questions from the campaign about how global warming might affect certain regions, or the extent to which an extreme weather event might be related to global warming.

Some experts say that the Democratic party’s adoption of science as a campaign issue — which Obama kick-started in 2008 — risks further polarizing thorny policy debates around scientific issues such as global warming. “The Democrats found that science was a good thing for them, just like historically strong support for the military was good for the Republicans,” says Daniel Sarewitz, co-director of Arizona State University’s Consortium for Science, Policy and Outcomes in Washington DC (and a regular contributor to Nature). “If the Democrats are the party of science, and you are a Republican, what does that make you think?”

But Holtz-Eakin says that the Trump campaign’s apparent decision to forgo science advice is a reflection of Trump himself, not of Republican priorities. In 2008, he notes, the McCain campaign consulted scientists to formulate its positions on issues such as global warming — just as Clinton has done.

Obama’s top scientist talks shrinking budgets, Donald Trump, and his biggest regret

With just over three months until the election, there is still a chance that Trump will assemble his own coterie of science advisers, says Andrew Rosenberg, who heads the Center for Science and Democracy at the Union of Concerned Scientists in Cambridge, Massachusetts. Doing so not only informs policy positions, it builds relationships that are useful after the election, when the winning candidate begins to assemble a government.

“These things widen the network,” Rosenberg says. “I know it’s happening with the Clinton campaign, and at some point I would expect it would happen with the Trump campaign.”