That would be Ron Paul (Andrew Sullivan's candidate). From Steve Benen's Carpetbagger Report:
For a presidential candidate, in 2007, to concede disbelief in evolution doesn’t reflect well on their understanding of facts and evidence. If they reject the overwhelming proof on modern biology, how will they deal with evidence regarding global warming? Or stem-cell research? Or a public health emergency? Or any public policy that deals with science?
Lawrence Krauss, a professor of physics and astronomy at Case Western Reserve University and chair of the Physics Section of the American Association for the Advancement of Science, recently had a good op-ed in the Wall Street Journal about science and the presidential candidates in general.
The day before the most recent Democratic presidential debate, the media reported a new study demonstrating that U.S. middle-school students, even in poorly performing states, do better on math and science tests than many of their peers in Europe. The bad news is that students in Asian countries, who are likely to be our chief economic competitors in the 21st century, significantly outperform all U.S. students, even those in the highest-achieving states. . . .
America’s current economic strength derives from the investments in fundamental research and technology made a generation ago. Future strength will depend upon research being done today. . . .
Can a president who is not comfortable thinking about science hope to lead instead of follow? […]
[T]here is a popular understanding that science and technology will be essential to meet the challenges we face as a society. When reports began to surface warning that the avian flu might become a threat to humans, for example, everyone from the president down called for studies to determine how quickly the virus might mutate from birds to human beings. No one suggested that “intelligent design,” for example, could provide answers.