It gets really confusing if you read the legal history of the FDA trying to control e cigs. Evidently, the courts say they have to be classified as "tobacco products", but legislation in place makes this impossible:
"The Food and Drug Administration (FDA) classified electronic cigarettes as drug delivery devices and subject to regulation under the Food, Drug, and Cosmetic Act (FDCA) prior to importation to and sale in the United States. The classification was challenged in court, and overruled in January 2010 by Federal District Court Judge Richard J. Leon, citing that "the devices should be regulated as tobacco products rather than drug or medical products."[36] Judge Leon ordered the FDA to stop blocking the importation of electronic cigarettes from China and indicated that the devices should be regulated as tobacco products rather than drug or medical devices.[37]
In March 2010, a US Court of Appeal stayed the injunction pending an appeal, during which the FDA argued the right to regulate electronic cigarettes based on their previous ability to regulate nicotine replacement therapies such as nicotine gum or patches. Further, the agency argued that tobacco legislation enacted the previous year "expressly excludes from the definition of 'tobacco product' any article that is a drug, device or combination product under the FDCA, and provides that such articles shall be subject to regulation under the pre-existing FDCA provisions."[38] On 7 December 2010, the appeals court ruled against the FDA in a 30 unanimous decision, ruling the FDA can only regulate electronic cigarettes as tobacco products, and thus cannot block their import.[39] The judges ruled that such devices would only be subject to drug legislation if they are marketed for therapeutic use E-cigarette manufacturers had successfully proven that their products were targeted at smokers and not at those seeking to quit. The District of Columbia Circuit appeals court declined to review the decision blocking the products from FDA regulation as medical devices on 24 January 2011".