President Barack Obama has put a respectably high price tag on his preschool proposal -- $75 billion over the next 10 years. The spending would start modestly, amounting to $1.3 billion in the first year, but rise to about $10 billion annually by 2020. That would go a long way toward helping states create and expand programs for the poorest American 4-year-olds.

Added to that, in the president's budget released yesterday, is a bonus for teenagers and others well beyond preschool age: Obama suggests paying for the preschool plan by almost doubling the federal tax on cigarettes, to $1.95 a pack from $1.01. History shows that when cigarette taxes rise, consumption drops, especially among the youngest smokers.

A 62-cent increase in the tax in 2009, for instance, led to an 8.3 percent drop in cigarette sales, according to the Campaign for Tobacco Free Kids.

A similar funding mechanism is working in California where a 50-cents-a-pack state cigarette tax is paying for a variety of services for children five and younger, including preschool.

While tobacco taxes are good public health policy, however, they're not a good permanent source of money for early education. If the 94-cent tax increase works to get people to stop smoking, the funding stream will necessarily diminish.

Other measures taken to discourage smoking -- public education campaigns and smoking-cessation clinics, for example -- would similarly reduce funding, as Michael Siegel, a professor of community health sciences at Boston University, points out. (Tobacco tax money is more logically spent on anti-smoking programs and treatments for smoking-related health problems, which require less funding as more people quit smoking.)

The Obama preschool program may largely avoid this problem by remaining temporary. The idea, the administration has suggested, is to jump-start states' pre-kindergarten offerings, not to build a permanent federal program. States would work in partnership with the U.S. Department of Education and develop their own funding streams. Ideally, in time, the states would pick up most of the cost of preschool and pay for it as they pay for K-12 education.

That is, assuming Congress allows the preschool plan to get started in the first place.

(Mary Duenwald is a member of the Bloomberg View editorial board.)