Some of the Republican presidential candidates have dismissed medical marijuana as unnecessary or “too dangerous.” Now they’re being offered $10,000 to come up with the scientific evidence.

The Marijuana Policy Project, a group advocating the use of medical marijuana, will be in New Hampshire next week with a mobile billboard offering to contribute $10,000 to the campaigns of Rudy Giuliani, John McCain or Mitt Romney if any of the candidates can substantiate their statements about medical marijuana.

Before any of the candidates tries for that money, I’d recommend taking a look at this study showing a way to administer medical marijuana without patients inhaling harmful smoke. Or this one showing that marijuana offered pain relief comparable to morphine.

Somehow, though, I don’t think any of them will be poring over those studies. Now that medical marijuana has become an issue on the campaign trail — the candidates have been getting visibly irritated at the continual questions at their town hall meetings — the GOP candidates seem to have decided the best course is to try ignoring it. Here’s a collection of videos showing Mr. Giuliani, Mr. McCain and Mr. Romney dodging the question when asked if they’d continue the federal policy of raiding medical marijuana clinics and arresting patients in states where medical marijuana has been legalized.