President Obama smoked pot in high school. Why is he against legalizing marijuana?

A new biography details Barack Obama's use of marijuana in high school and college, not unusual for a young man at that time. As president, Obama has taken a tougher line on drug use, including marijuana for medical reasons.

When he was “drug czar” in the administration of George H. W. Bush, William Bennett was asked if he’d ever smoked marijuana.

“No,” he reportedly said, grinning. “Besides, I was very young at the time.”

Or as former president George W. Bush said when deflecting questions about his drug use decades ago, “When I was young and irresponsible, I was young and irresponsible.”

“Youthful indiscretion” is a phrase often heard among politicians in recent years – typically referring to extra-marital affairs (sometimes occurring when the adulterer was in his 40s).

When he wasn’t being questioned (or impeached) about his alleged womanizing, former president Bill Clinton acknowledged having smoked marijuana “a time or two” when he was a Rhodes Scholar in England – although he was quick to point out that he “didn't inhale and never tried it again.”

How much do you know about marijuana? Take our quiz.

Now it’s Barack Obama’s turn to come under scrutiny for drug use.

In his new biography “Barack Obama: The Story,” to be published next month but widely excerpted in the press, David Maraniss of the Washington Post details Obama’s marijuana smoking when the future president was a high school student in Hawaii.

With a group of friends who called themselves “The Choom Gang” (mostly basketball buddies) the future president rode around in a VW van or hung out at a favorite island spot up Mount Tantalus on Oahu, smoking marijuana and sometime drinking beer.

"They parked single file on the grassy edge, turned up their stereos playing Aerosmith, Blue Öyster Cult, and Stevie Wonder, lit up some 'sweet-sticky Hawaiian buds,' and washed it down with 'green bottled beer' (the Choom Gang preferred Heineken, Beck's, and St. Pauli Girl)," Mr. Maraniss writes. "No shouting, no violence, no fights; they even cleaned up their beer bottles. This was their haven, in the darkness high above the city and the pressures of Punahou” – the private college-prep school Obama attended from fifth grade through graduation in 1979.

The news that Obama used drugs for a while years ago – which is not really news; he acknowledges the fact in his autobiography “Dreams from My Father” – probably doesn’t shock or even surprise many Americans versed in today’s arguments about the failings of the “drug war” and the legalization of marijuana, including for medicinal purposes.

“New data … show that marijuana use is becoming a more acceptable behavior among teens, and heavy marijuana use is now at disturbingly high levels,” the Partnership for a Drug-Free America reported this month.

“Nearly half of teens (47 percent) have ever used marijuana – a 21 percent increase since 2008. Additionally, two out of every five teens (39 percent) have tried marijuana in the past year, up from 31 percent in 2008,” according to the report. “Past-month use has increased 42 percent from 19 percent in 2008 to 27 percent in 2011. Heavy monthly use (20 or more times) is up 80 percent from 5 percent to 9 percent in 2011.”

And of course the Woodstock era in which the parents of today’s teens grew up – the 1960s and 70s – launched a new public attitude about marijuana. “If you can remember the 60s, you weren’t really there,” goes the old joke, variously attributed to comedian Robin Williams or singer Grace Slick of The Jefferson Airplane. Who of a certain age can forget "White Rabbit?"

But back to Obama, who falls between the two generations. What’s his attitude as an adult toward marijuana?

Speaking at Northwestern University in Chicago in 2004 he said, “In terms of legalization of drugs, I think, the battle, the war on drugs has been an utter failure and I think we need to rethink and decriminalize our marijuana laws.”

“But I’m not somebody who believes in legalization of marijuana,” he said. “What I do believe is that we need to rethink how we are operating in the drug wars, and I think that currently, we are not doing a good job.”

As president (and perhaps as the father of 13- and 10-year olds), he’s taken a tougher line.

The administration’s National Drug Control Strategy, issued last year, states: “Marijuana and other illicit drugs are addictive and unsafe especially for use by young people. The science, though still evolving in terms of long-term consequences, is clear: marijuana use is harmful. Independent from the so called ‘gateway effect’ – marijuana on its own is associated with addiction, respiratory and mental illness, poor motor performance, and cognitive impairment, among other negative effects.”

On medical marijuana, the strategy states:

“Despite successful political campaigns to legalize ‘medical’ marijuana in 15 states and the District of Columbia, the cannabis (marijuana) plant itself is not medicine. While there may be medical value in some of the individual components of the cannabis plant, the fact remains that smoking marijuana is an inefficient and harmful method for delivering the constituent elements that have or may have medicinal value…. To date, the [Food and Drug Administration] has not found smoked marijuana to be either safe or effective medicine for any condition.”

Obama’s “drug czar,” Gil Kerlikowske (Director of the White House Office of National Drug Control Policy), points out that most adult males arrested on misdemeanors and felonies test positive for an illegal drug, including marijuana, at the time of their arrest – ranging from 64 percent in Atlanta to 81 percent in Sacramento.

Mr. Kerlikowske (the former police chief of Seattle) advocates a “third way” between legalization and strict criminalization – a focus on treatment and prevention.

It’s the kind of thing the teen-aged Barack Obama probably didn’t think about when he was hanging out with “The Choom Gang.”

How much do you know about marijuana? Take our quiz.