The Centers for Disease Control and Prevention will hold closed meetings in the coming weeks on what to do about possible bioterrorism and the smallpox vaccine.

Americans are smart enough to choose whether to take the vaccine. Therefore, it should be made available to the public.

Unfortunately, the current policy leaves Americans with no choice in the matter — no freedom to choose what may be most effective for their own security and peace of mind. In the case of a bioterrorist attack using smallpox, Americans cannot immunize themselves beforehand with the vaccine. The government won't give its own citizens access to the vaccine, even though it's in stock and even though Vice President Cheney's recent comments on terrorism show that the threat of smallpox bioterrorism is real.

That's unacceptable.

At its June 19-20 meeting, the CDC will likely produce policy guidance for smallpox vaccination. The CDC should decide against perpetuating the current "ring containment" strategy, whereby government doles out smallpox vaccinations only after a known outbreak in the hope of containing the spread of the virus. That may make sense for a natural outbreak in a rural area, but such a policy would likely be disastrous against smallpox bioterrorism.

Although eradicated as a disease in 1978, when the government mandated the vaccination of all children, smallpox is still a devastating virus. It has a 30 percent or higher fatality rate among unvaccinated persons (Americans born after 1972 have not been vaccinated) and is easily transmitted. Smallpox has killed more people than any other infectious disease in human history; in the 20th century, it killed nearly three times more people than all the wars combined (400 million vs. 111 million).

Compared to the anthrax-laden letters distributed in the mail, the smallpox virus is easier to disperse. It can be aerosolized and released into the air in a crowded place, such as a shopping mall, sports stadium, or airport. The virus need not even be weaponized. Suicide terrorists could infect themselves with the virus and transmit it to others by coughing and sneezing, releasing millions of deadly virus particles through the air.

Indeed, a smallpox attack could occur at multiple locations and may not be immediately known (the initial symptoms are flu-like; it could be 12 or more days before smallpox is diagnosed). As a result, the virus could spread widely and kill thousands before the first vaccinations are administered (the vaccine must be given within four days of being exposed to be effective).

Moreover, given a dense and highly mobile population, the virus is likely to spread much faster and wider (including to other countries) than a ring containment strategy can keep up with. In the inevitable post-attack panic and confusion, the medical infrastructure would be overwhelmed by millions of people demanding immediate vaccination.

Rather than leaving the entire population at risk and responding to a smallpox attack after the fact, a better approach would be to take preventative measures now. The U.S. government is currently in possession of 15 million doses of smallpox vaccine that, according to a study published by the New England Journal of Medicine, can be effectively diluted 5-fold, perhaps even 10 times.

Combined with some 85 million additional doses of newly discovered smallpox vaccine, there is a sufficient supply to allow for voluntary vaccination. The smallpox vaccine supply should be about 450 million doses by the end of this year.

Because there are known risks with the smallpox vaccination, particularly for pregnant women and those with weakened immune systems, individuals should be allowed to make a voluntary, informed decision (in consultation with a doctor) to understand, manage, and mitigate those risks. But the government's withholding of the vaccine until after an attack — forcing people to make the stark choice of having to accept the risks of vaccination or be exposed to the deadly smallpox virus — is not an acceptable policy in a society that values individual life and liberty.

Even if only a fraction of the population were vaccinated beforehand, a "community immunity" effect would occur that lowers the rate of transmission of the disease and significantly increases the chances of success of a ring containment strategy. As a result, the chances of a successful attack would be lowered, which could also have a deterrent effect and prevent such an attack from occurring. But that won't happen if Americans aren't given the freedom to choose the vaccine.

Vice President Cheney recently warned, "The prospects of a future attack against the United States are almost certain." Even a partially vaccinated population against smallpox is more effective than leaving Americans unprotected and at risk, hoping that a pound of cure will work after the fact.

Charles V. Peña is senior defense policy analyst at the Cato Institute.