“That is how black markets work: prohibiting something..."

“That is how black markets work: prohibiting something that is highly desired does not make the desire go away but merely ensures that the supply of that good is provided in the most dangerous and undesirable manner possible, and endows criminal sectors of society with additional wealth and power.” -Page 131 of The Revolution, A Manifesto

“The failure of the federal war on drugs..."

“The failure of the federal war on drugs should be clear enough from one simple fact:  our government has been unable to keep drugs even out of prisons, which are surrounded by armed guards.” -Page 131 of The Revolution, A Manifesto

"Clogging our courts and prisons with cases involving..."

"Clogging our courts and prisons with cases involving people found in possession of tiny quantities of prohibited substances, and who have never done any physical harm to anyone, makes it all but impossible to devote the necessary resources to tracking down the violent criminals who really do threaten us.  Over the past two decades more people have been imprisoned on drug offenses than for all violent crimes put together.  And that is not to mention the continued erosion of our civil liberties for which the drug war has been responsible."  -Page 131 of The Revolution, A Manifesto

"The resulting Marijuana Tax Act of 1937..."

"The resulting Marijuana Tax Act of 1937- yes, federal prohibition is really just seven decades old- had little to do with real science or medicine, and a lot to do with petty ethnic grudges, careerism in the Bureau of Narcotics, and disinformation and propaganda in the popular press, where yellow journalism still lived.  

Hearings on this important matter took a grand total of two hours, very little of which had anything to do with the health effects of marijuana, the alleged reason behind the proposed prohibition. * [*I am indebted for much of this discussion to Charles Whitebread and Richard Bonnie, Marihuana Conviction: The Legal History of Drugs in the United States (Charlottesville: University of Virginia Press, 1974).

A grand total of two medical experts testified on the subject.  One alleged expert was James Munch, a professor who claimed to have injected 300 dogs with the active ingredient in marijuana, and that two had died.  When asked whether he had chosen dogs for the similarity of their reactions to those of human beings, he shrugged, “I wouldn’t know; I am not a dog psychologist.”

We can be fairly certain that this professor had not injected these dogs with the active ingredient in marijuana, since that ingredient was synthesized for the first time in a laboratory in Holland years later.  But keep this gentleman in mind for a moment.

The other expert who testified was William Woodward, who represented the American Medical Association.  He denounced the legislation as medically unsound and the product of ignorance and propaganda. “The American Medical Association knows of no evidence that marihuana is a dangerous drug,” he said.  To which one congressman replied, “Doctor, if you can’t anything good about what we are trying to do, why don’t you go home?”

In Congress, the entire debate on national marijuana prohibition took about a minute and a half.  

“Mr. Speaker, what is this bill about?” asked a congressman from New York. 

“I don’t know,” came the reply.  “It has something to do with a thing called marihuana.  I think it’s a narcotic of some kind.”

Then a second question from the congressman: “Mr. Speaker, does the American Medical Association support this bill?”

The AMA opposed the bill, as we’ve seen.  But the Speaker replied, “Their Doctor Wentworth [sic] came down here.  They support this bill 100 percent.”

And with that untruth ended the entire congressional debate on the prohibition policy.  

[....]

You can guess what happened next.  James Munch, the one person at the conference who agreed with Anslinger on marijuana, was named the Official Expert on marijuana at the Federal Bureau of Narcotics.  One person agrees with the government’s position and he is appointed the Official Expert.  If that doesn’t sum up how the government operates, I don’t know what does.” -Pages 128 & 129 of The Revolution, A Manifesto

".... people's opinions on this issue are so deeply and fervently..."

".... people's opinions on this issue are so deeply and fervently held that is can be very difficult to persuade them to revisit the evidence  dispassionately. 

But revisit it we must. We seriously mistake the function of government if we think its job is to regulate bad habits or supplant the role of all those subsidiary bodies in society that have responsibility for forming our moral character. Our misplaced confidence in government has once again had exceedingly unpleasant results. 

"A barrage of research and opinion," writes economist Dan Klein, "has pounded [the drug war] for being the cause of increased street crime, gang activity, drug adulteration, police corruption, congested courts and overcrowded jails. Drug prohibition creates a black-market combat zone that society cannot control."

The drug war has wrought particular devastation in minority neighborhoods, as decent parents find themselves consistently undermined when they try to teach good values to their children. When the lucrative profits from black market in drugs make drug dealers the most ostentatiously prosperous sector of society, it is much more difficult for parents to persuade their children to shun those profits and pursue a much less remunerative, if more honorable, line of work. Putting an end to the federal drug war would immediately pull the rug out from under the drug lords who have unleashed a reign of terror over our cities. 
...
The conservative economist Thomas Sowell finds the whole thing more utopian than conservative: "What would make still more sense [than the current policy] would be to admit that we are not God, that we cannot live other people's lives or save people who don't want to be saved, and to take the profits out of drugs by decriminalizing them. That is what destroyed the bootleggers' gangs after Prohibition was repealed. 
....
What is more, the law cannot make a wicked person virtuous. The law is simply incompetent here. What the law can do is provide the peace and order within which men can conduct their affairs. We ought not to shirk our own responsibility by looking to politicians- who are not exactly known for living beyond more reproach themselves - to carry out so important a function. 

When you actually study the beginnings of the federal war on drugs, you uncover a history of lies, bigotry, and ignorance so extensive it will leave you speechless." -Pages 125-127  of The Revolution, A Manifesto