In the letter, Mr. Leavitt said his department supported efforts to encourage adults who smoke to quit and to keep children from starting, and he said the department would spend $680 million toward those ends in 2008.  But he said the administration had “serious concerns” that the bill could overload the F.D.A. by piling on “significant added responsibility” that is inconsistent with the agency’s mission of ensuring the safety of food, drugs and medical devices.  The new regulations included in the bill may cost more to impose than the bill raises in revenues through user fees and taxes, the letter said.  “This could result in diverting personnel and resources from current programs within the F.D.A., with the potential to seriously undermine the public health,” the letter said.  Furthermore “adding tobacco to F.D.A.’s regulatory responsibilities could also leave the public with the misperception that tobacco products are safe, or at least safer, with the F.D.A. regulating them,” the letter said, predicting a “perverse and unintended consequence of lowering the perceived risk of tobacco.”  The legislation has the support of the nation’s largest cigarette company, Philip Morris USA, but most other cigarette makers oppose it.  The letter also raises new questions about the bill’s treatment of menthol cigarettes.  The bill would ban candy, fruit and spice-flavored cigarettes, including clove cigarettes, but menthol cigarettes would be exempt from the ban. Menthol cigarettes make up 28 percent of the United States cigarette market.  Indonesia, which exports a clove-flavored cigarette called kretek, has objected to the favorable treatment of menthol over other flavorings, Mr. Leavitt said. “The government of Indonesia has repeatedly objected to the bill on the ground that this disparate treatment is unjustified and incompatible with W.T.O. trade rules,” Mr. Leavitt wrote, in reference to the World Trade Organization.  In voicing concern about the menthol exemption, the administration finds itself on the side of black antismoking advocates who have criticized the bill.  Menthol cigarettes are chosen by about 75 percent of black smokers. Researchers have long worried that menthol may play a role in the disproportionate diagnosis of smoking-related cancers among blacks, possibly by masking tobacco’s harsh taste, and some research suggests that menthol smokers find it more difficult to quit.  Supporters of the bill have said that, although menthol is exempt from the ban on flavorings in the bill, the F.D.A. would have the power to limit or ban menthol if it is proved harmful. Some members of the Congressional Black Caucus have said they would press for a floor amendment of the bill to impose additional restrictions on menthol cigarettes or require a study of them.  A version of this article appears in print on , on Page C4 of the New York edition with the headline: Veto Seems More Likely In Battle Over Tobacco Bill. Order Reprints| Today's Paper|Subscribe
The Bush administration has said it “strongly” opposes the effort to give the Food and Drug Administration regulatory authority over tobacco.