Noah Kristula-Green proposes that a moderator at a Republican presidential debate ask the candidates, "Raise your hand if you have any doubts that President Obama was bor in the United States.”
I think Green is on the right track here, but I don't think he has the wording right. What the top Republicans are doing is finessing the issue. They say they believe Obama was born in the U.S., but they insist on framing it as a matter of opinion, leaving open the possibility that people can intelligently disagree on the topic. Green's wording lets them persist in that evasion. Good political questions make it hard for candidates to evade issues that way.
The better wording would be something like, "Raise your hand if you think there is any legitimate reason whatsoever to doubt that President Obama was born in the United States." When questioning individual candidates, a good way to get into the issue would be to ask them first if George W. Bush was born in the United states, then ask about Obama, and then -- if they phrased the latter response in more qualified terms than the former -- ask them why.