Pat Robertson, the well-known Christian broadcaster, attracted lots of attention recently after saying he supports decriminalizing marijuana and treating it like alcohol. His position is surprising and quite bold -- but actually not much bolder than the position taken by other conservative icons in recent years.

Two years ago, Sarah Palin, who has admitted to using marijuana but opposes legalization, said,

I think we need to prioritize our law enforcement efforts. And if somebody's gonna smoke a joint in their house and not do anybody else any harm, then perhaps there are other things our cops should be looking at to engage in and try to clean up some of the other problems that we have in society.

Relatively speaking, she said, marijuana is a "minimal problem."

If one looks at the 2012 presidential race, we find an incumbent president who has admitted to using marijuana (among other drugs) but who opposes legalization. On the Republican side, Ron Paul supports legalization, and the two "conservative" challengers to Mitt Romney -- Newt Gingrich and Rick Santorum -- both have admitted smoking marijuana in their youth, but join former users Obama and Palin in opposing legalization.

As for the public, the most recent Gallup Opinion poll found that 50 percent support legalization (an all-time high, so to speak) while 46 percent oppose. This support will be put to the test this year as several states consider reforms to recreational marijuana use. Then again, because the federal prohibition will trump state laws, perhaps nothing will be decided.

Indeed, if the debate over marijuana policy consists only of legalization versus prohibition, the current stalemate could remain for several years. But there is a way to bridge the gap between those who think pot should remain illegal but be a low priority for law enforcement and those who think it should be legal and regulated like alcohol.

A path forward can be found in something else that Pat Robertson said. Of the United States' extraordinarily high incarceration rate, Robertson said,

It's completely out of control. Prisons are being overcrowded with juvenile offenders having to do with drugs. And the penalties, the maximums, some of them could get 10 years for possession of a joint of marijuana. It makes no sense at all.

Robertson is right. Despite the growing support for legalizing marijuana, federal law still imposes extraordinarily heavy punishment for growing it: five and 10-year mandatory minimum prison sentences depending on the weight of the marijuana an offender has or the number of marijuana plants he is growing.

In 2010, federal convictions for marijuana-related offenses exceeded convictions for any other drug, and a full 44 percent of marijuana offenses carried a five- or 10-year mandatory sentence. Fortunately, most were spared the mandatory minimum because the crime was their first felony offense. But nearly 1,000 people in 2010 were subject to a lengthy mandatory minimum at sentencing.

These long sentences do not reflect the choices of federal judges. Mandatory minimums by their very nature take away any choice or discretion judges have to impose a sentence that fits the crime and individual offender. But that doesn't mean that federal judges do not have a view on the appropriateness of marijuana sentences. When asked by the U.S. Sentencing Commission in 2010, more than half of all federal judges responded that mandatory minimum penalties for marijuana offenses were too high.

Congress is not likely to decriminalize marijuana any time soon. Likewise, the states will probably not be allowed to opt out of the federal drug laws. Reasonable people can disagree with whether this is a good or bad thing -- and given recent poll numbers, it appears that reasonable people are equally divided.

What is not reasonable, however, is to keep in place a two-decade-old punishment scheme that locks people up for extraordinarily harsh prison terms for engaging in conduct that half of the country thinks should be legal -- conduct in which more than half of this year's presidential contenders engaged. Common sense should compel Congress to eliminate or drastically reform marijuana mandatory minimum prison sentences.