But we share a right to press candidates about their views on the boundary [of religion and science]. After all, determined efforts have been made to introduce scriptural versions of the age of Earth or of "intelligent design" in science classrooms. We need to know the candidates' qualifications for understanding and judging science, and for speaking intelligently about science and technology to the leaders of other nations in planning our collective global future. I don't need them to describe their faith; that's their business and not mine. But I do care about their scientific knowledge and how it will inform their leadership.
I care about their scientific knowledge and how it will inform their leadership, too; but I get chills down my spine at this talk of Presidents "judging" science or "planning our collective global future", since both are well outside the jurisdiction even of Presidents. It's good for Presidents to be informed -- good for them to be informed about a lot of things, actually. For instance, I would be inclined to agree with arguments for grilling candidates about their knowledge of geography, the political structures of other nations, military organization, and constitutional law. But we don't elect Presidents to be encyclopedias; we elect them to put into execution the laws Congress passes, to be commander in chief of the armed forces, to grant pardons and reprieves, to make treaties under the watchful eye of the Senate, to appoint higher-level officials, and to uphold the Constitution. I don't read anywhere in the Constitution about the President having any special authority to 'judge science' or to 'plan the global future'. When we put the matter in those terms, we have already put it in the wrong terms. We want our candidates to be reasonably familiar with scientific matters for the same reason we want them to be reasonably familiar with American history, or with moral philosophy, or with economics, or with more than one language: namely, it is much to be preferred if they have the tools to fulfill their constitutional duties in a reasonable competent, stable, and informed way. To the extent (and it is usually a limited extent) that one of these things will help them do so, it's important to look for it. But this is not because we want Presidents to understand and judge theories in quantum physics and to plan the future course of global medical research. And so it is, mutatis mutandis, with almost every political office in the land.
I do think the issue of science policy can be important in politics -- but for the most part this is true only when electing school board officials and the like. Last I checked, Presidents do not decide school board policy or monitor curricula at your closest high school; and if you have to go all the way to the White House to guarantee that students are taught well at the local elementary school, you've already messed up your system of education beyond repair. Fortunately, I don't think we've gone that far; as some people have to keep being reminded, the reason "determined efforts have been made to introduce scriptural versions of the age of Earth or of 'intelligent design' in science classrooms" have largely failed so far has nothing whatsoever to do with federal or even state politics. The reason it has failed can be found in parents getting together and taking an interest in their own school and school district. If you really want science policy done properly in the United States, you have to appreciate which level of authority is most relevant to the point at hand.
Of course, personal preferences might always come in. I like to know what non-English languages a candidate speaks well. (This time around, as far as I can determine on limited information: Spanish -- Richardson and possibly Paul; French -- Romney, Gravel, and Richardson; Indonesian -- Obama; a few odds and ends and partials and unknowns scattered around the others.) I also like to have an idea of the sort of education a candidate has. (Ron Paul has an M.D., and has practiced as an ob/gyn; Ken Mesplay of the Green Party has a Ph.D. in biochemical engineering; George Phillies of the Libertarian Party has a Ph.D. in physics, which he teaches at Worcester Polytechnic; Clinton, Edwards, Obama, Giuliani, Romney, and Thompson appear to have J.D.'s; the rest are rather diverse.) But these are bits and pieces, and a matter of personal preference, not general policy.