When a writer has previously stated his closest political ties are to the Libertarian party and then pens a headline that proposes a new tax, there better be an explanation. Let me begin mine by posing a philosophical question.

What do you do when an important belief of yours proves to be ineffectual in a specific situation?

I firmly believe, for instance, that the only real discipline is self-discipline, so while performing my other job as a language arts teacher of seventh graders, I attempt to create an environment that encourages that. It's an environment, I'd like to think, that the students prefer and appreciate, and the one most conducive to engendering an individual's thought process, a trait of true learning.

But the litmus test for any practice or policy is its effectiveness, and the fact of the matter is that there are some seventh graders who are not emotionally mature enough to control their behavior through self discipline.

As a result, I'm forced to act in a manner contrary to my beliefs and dole out the discipline for them.

Does it make me happy? Hardly. But, in measured doses and most instances, it is effective. And it keeps the undisciplined from adversely affecting others in the class.

This, in a nutshell, is also my view on a statewide or nationwide soda tax. While I'd rather not be suggesting one, many healthy citizens are adversely affected and our current health care system is less effective without such a tax.

I realize to claim a kinship with the Libertarian party and then pooh-pooh the principle of unrestricted liberty, requires a powerful reason.

There is.

It's called externality, a secondary or unintended consequence, the term used by Kelly D. Brownell, Ph.D., and Thomas R. Frieden, M.D., in "Ounces of Prevention The Public Policy Case for Taxes on Sugared Beverages" published in the New England Journal of Medicine on April 30, 2009.

While I'm all for you eating or drinking whatever you want, I do not want others to be punished for it. Yet, as "Ounces of Prevention" states, that's happening.

Approximately half of the medical costs from obesity and overweight "are paid by Medicare and Medicaid at taxpayers' expense," and that cost is high, an estimated $79 billion last year with the cost continually rising.

So why does that merit an excise tax of one cent per ounce on soda and sugared beverages as "Ounces of Prevention" suggests? Because a link between soda ingestion and overweight and obesity has been clearly established.

In 2009, for instance, the California Center for Public Health Advocacy reported that Californian adults who drink one or more sugared sodas a day are 27 percent more likely to be overweight or obese than those who do not drink soda, a finding that supports an earlier study that discovered a child's likelihood of becoming obese increases 60 percent with each can of sugared beverage consumed per day.

Furthermore, a comprehensive overview of all germane research found the increasing consumption of sugared beverages correlates to an increasing risk of diabetes, a disease, according to a study released by the American Public Health Association in 2009, that if prevented increases the life of 50 year olds by 3.17 years and saves them $34,483 in lifetime medical costs.

But why a tax to reduce the consumption of soda and sugared beverages? Why not simply offer subsidies that encourage healthier eating habits?

Because a study published in 2010 in Psychological Science showed taxes to be more effective than subsidies in reducing calories. Moreover, subjects in the study actually took the money saved by subsidized healthy foods and splurged on unhealthy treats.

A more recent and less stringent experiment took place in one of Harvard's cafeterias. There, researchers used the equivalent of a tax to see whether they could change drinking habits.

For four weeks, researchers raised the prices of 20-ounce sugared sodas by 35 percent. As a result, sales dropped by 26 percent while sales of regularly priced diet sodas increased by 20 percent.

Later, researchers returned the prices to normal but placed posters throughout the cafeteria explaining the benefits of reducing consumption of soda by one can a day, such as a 50-percent reduction in the incidence of diabetes and a weight loss of up to 25 pounds in a year. Yet during the four weeks that the posters were displayed, sales of sugared soda did not change.

Since 1977, American soda consumption has approximately doubled to an average of 50 gallons per person per year. In that time, the increase of American adults who are overweight has more than kept pace, and the childhood obesity rate has tripled.

"Ounces for Prevention" estimates that "a penny-per-ounce excise tax could reduce consumption of sugared beverages by more than 10 percent," a reduction its authors believe would not occur through any other process.

While I'm not thrilled to write it, the tax makes sense. In this specific situation, the sacrifice of a personal liberty keeps other personal liberties in tact.