Jacob Sullum summarizes the good news:
Today the U.S. Court of Appeals for the D.C. Circuit ruled that the FDA may not ban electronic cigarettes as an unapproved "drug/device combination." The appeals court agreed with U.S. District Judge Richard Leon that the battery-powered e-cigarettes, which generate a smoke-free vapor containing nicotine derived from tobacco, are properly regulated as tobacco products. That means the FDA may regulate the marketing of e-cigarettes under the authority granted by the Family Smoking Prevention and Tobacco Control Act but may not treat them like a pharmaceutical product subject to strict clinical testing requirements (a trick it once tried with conventional cigarettes, only to be slapped down by the Supreme Court). The ruling is a victory not just for the companies that brought it, NJOY and Smoking Everywhere, but for smokers who use their products as replacements for ordinary cigarettes, which are far more hazardous.