Sen. Barack Obama (D-Ill.) recently said that, if elected president, he would end the federal raids on medical marijuana patients and their health care providers. That makes the Democratic field unanimous now — all would end the raids and allow the states to craft their own medical marijuana policy, free from federal interference. By contrast, just two of the remaining GOP candidates — Rep. Ron Paul (Texas) and Rep. Tom Tancredo (Colo.) — and none of the front-runners have promised to call off the raids. This is unfortunate for a party that once fancied itself the torch-bearer for federalism —...