Editor's note: William J. Bennett is the Washington fellow of the Claremont Institute. He was U.S. secretary of education from 1985 to 1988 and was director of the Office of National Drug Control Policy under President George H.W. Bush.

(CNN) -- From certain precincts on the left, notably Barney Frank, to certain precincts on the right, notably the editorial page of National Review, we are witnessing a new push to end the so-called war on drugs and legalize drug use, starting with marijuana. Indeed, Ron Paul, Barney Frank's co-sponsor in the latest legislative effort, said recently he would go so far as to legalize heroin.

It's a bad idea. My friends at National Review begin their case by stating the illegalization of drugs has "curtailed personal freedom, created a violent black market and filled our prisons." But the legalization of drugs, including marijuana, would exacerbate each of these problems.

Ron Paul, Barney Frank: End pot prohibition

Starting with the basics, keeping drugs illegal is one of the best ways to keep drugs out of the hands -- and brains -- of children. We know three things here: First, children who don't use drugs continually tell us one of the reasons they don't is precisely because they are illegal.

For example, since at least 1975, report after report has found that "perceptions of the risk and social disapproval of drug use correlate very closely with drug taking behavior." When those in the drug prevention community ask teens who don't use drugs why they don't, time and again, the answer comes back "because it's illegal." This, of course, explains why a greater percentage of teens abuse legal substances like tobacco and alcohol over illegal drugs such as marijuana -- even when they say marijuana is easily accessible.

Second, keeping drugs out of the hands of children is the best way to prevent drug addiction generally, as study after study has confirmed that if we keep a child drug free until age 21, the chances of use in adulthood are next to zero.

Third, we don't need to guess at hypothetical legalization schemes. Our experience with legally prescribed narcotics has already proven it, and we now have an epidemic. This, despite doing everything the theorists have asked, from oversight to regulation to prescription requirements.

Normalizing, de-stigmatizing, and legalizing illegal drugs lowers their price and increases their use. As a recent RAND study on California found, legalization of marijuana there would cut the price by as much as 80% and increase use from as little as 50% to as much as 100%. Just what California, just what our society, needs.

As for the current drug policies curtailing personal freedom, the question is: "Whose freedom?" The drug dealers', sure -- the drug consumers, no.

As any parent with a child addicted to drugs will explain, as any visit to a drug rehab center will convey, those caught in the web of addiction are anything but free. And it is not because of their incarceration or rehabilitation, it is because of the vicious cycle of dependency, waste and brain damage addiction and abuse cause.

Let us make no mistake about this, either: Marijuana is much more potent and causes much more damage than we used to know. Today's marijuana tests on average at more than 10% THC (the psychoactive ingredient). We are even seeing samples of more than 30% THC. This is compared to the relatively lower levels of THC most legalizing proponents were more familiar with in generations past (under 4% in the early 1980s, even lower in the 1960s).

Chronic adolescent marijuana use has been found to be associated with "poorer performance on thinking tasks, including slower psychomotor speed and poorer complex attention, verbal memory and planning ability." We are seeing study after study finding adolescent marijuana use responsible for "disrupted brain development" in teens. Worse, we are seeing more and more studies showing teen marijuana use linked to psychosis.

As for the high incarceration rates for simple marijuana use and possession, it is a myth. As government documentation actually shows, over 97% of sentencing on federal marijuana-related charges is for trafficking, less than 2% is for simple possession. Indeed, the only National Review authority with federal prosecutorial experience that I know of backs this point up: "Actual enforcement is targeted at big distributors. People who merely possess drugs for personal use well know they are substantially safe no matter what the statutes say."

We have had a fair amount of experience with legalization and decriminalization schemes. What are those communities now saying? Citizens are trying to put the genie back in the bottle, from Northern California (where residents have complained that medical marijuana has "spawned crime, drug cartels and teenage pot use"), to the Netherlands (where drug tourism, use by minors, and border trafficking has increased), to England (where apologies have been made for endorsing decriminalization in light of the subsequent growth of teen drug treatment needs), to Colorado (where easy access has increased demand, "made a mockery" of the legal system, and is increasingly endangering public safety).

We have an illegal drug abuse epidemic in this country and it has not been given enough attention. But the cultural messages, as much as the law, matter. When we unified on this, as we once did, drug use went down. When we let up, as we now have, use increases.

The libertarian experiment promoted as a novel theory by some will only make things worse. More legalization equals more damage, waste, crime and abuse. Not less. That is why it is no time to surrender.

The opinions expressed in this commentary are solely those of William J. Bennett.