It is astonishing how often the mainstream press lets people get away with lies. Advocates can say anything and the press isn’t likely to challenge the statement in the same story. Whether it’s assertions that “Christianity is under attack” or that Social Security will be bankrupt by 2042,” powers that be can make statement that are patently untrue.

So it has been for a long time with marijuana. Several years ago, a friend of mine in Mississippi made me aware of a study at the University of Mississippi called the Potency Monitoring Project. For years, it has been taking samples of MJ available throughout the country and tested its potency. A researcher there told me then that the hype about MJ being “far more potent” is simply not true.

And yet you hear it in virtually every story about MJ, including the recent report that MJ arrests are way up.

The focus of the drug war in the United States has shifted significantly over the past decade from hard drugs to marijuana, which now accounts for nearly half of all drug arrests nationwide, according to an analysis of federal crime statistics released yesterday.

The study of FBI data by a Washington-based think tank, the Sentencing Project, found that the proportion of heroin and cocaine cases plummeted from 55 percent of all drug arrests in 1992 to less than 30 percent 10 years later. During the same period, marijuana arrests rose from 28 percent of the total to 45 percent.

And then today, we have an op-ed by former HEW secretary Joe Califano (not online) in today’s Washington Post that makes several claims that simply aren’t true, including the one about potency, as observed by Chicago Trib columnist Clarence Page a couple of years ago.

[[Then director of the Office of National Drug Control Policy John P.] Walters tries to frighten us Baby-Boomer parents by warning us that “today’s marijuana is different from that of a generation ago, with potency levels 10 to 20 times stronger than the marijuana with which they were familiar.”

As a Woodstock-generation parent of a wise 13-year-old boy, I took great interest in that statement. Unfortunately, as I noted, Walters didn’t say where he got that “whopper” of a statistic.

I had cited a federally funded study published in the January 2000 Journal of Forensic Science, which found the average THC (that’s the active ingredient that makes people high) content in confiscated marijuana had only doubled to 4.2 percent from about 2 percent from 1980 to 1997.

That brought a response from Walters claiming that I didn’t cover a long enough period. THC content averaged less than 1 percent in 1974, he said. But “by 1999, potency averaged 7 percent.”

“The THC of today’s sinsemilla (high-grade marijuana) averages 14 percent and ranges as high as 30 percent,” he said.

“Wow,” as my “deadhead” friends might say. “That must be some killer weed, dude.”

I tried once again and actually reached Walters this time. After conversations with him and some of his expert advisers, we agreed to disagree on the key question: What are the chances that your little Johnny or Jane will latch onto some of that knockout grass?

That depends on how you interpret the available data. The latest quarterly report by the University of Mississippi’s Potency Monitoring Project (which examined 46,000 samples of seized marijuana nationwide) found an average potency of 6.68 percent. Actual potencies ranged as high as 33.12 percent THC content for some extraordinarily potent sinsemilla confiscated by the Oregon state police to as low as 1 percent THC or no THC at all (Somebody apparently got burned) for grass confiscated elsewhere in the country.

But it is hard to estimate based on available data how common or how rare the high-octane dope happens to be. Purchasing weed is an art in itself. Everyone seeks the “preemo” stuff. Every dealer promises it. Fewer actually deliver.

Nor is it at all clear that the marijuana commonly available in the 1960s and 1970s really was all that weak. Potency studies at the time were plagued by such problems as small samples and poor storage in police lockers.

In his column, Califano passes as facts other exaggerations or misrepresentations, such as the assertion that MJ dependence has jumped drastically among teenagers, that MJ causes depression and other mental problems and that MJ is highly addictive.

For more on the ongoing lie campaign by our government, see clarifications and rebuttals to these assertions here, where the references to the original research are given, as opposed to Califano’s rhetoric.

As the father of three teenagers, I can tell you it doesn’t help when well-meaning people exaggerate and misrepresent the facts. Once some of these facts are perceived by teenagers as wrong after first-hand experience, all the good infromation becomes suspect, too. Then they believe nothing, and that is a shame.