BOB GARFIELD: Geoffrey Stone is a professor of constitutional law at the University of Chicago. He says that if the public and legislators are often weak in the knees about the First Amendment, the judiciary, by and large, has been consistent and resolute, this no more plainly than in 1977, when the Supreme Court granted the American Nazi Party the right to parade its hatreds before the scarred survivors of Nazism.

GEOFFREY STONE: Individuals who had survived the Holocaust were appalled at the prospect that the Nazis would march in their home town, and they basically said that, in part, the emotional distress that would be created by this event justified prohibiting the Nazis from marching. And the courts eventually held, no, that the First Amendment gave the Nazis the right to march, and emotional distress was not a justification for restricting someone’s free speech.

BOB GARFIELD: Now, there’s inflicting offense and emotional pain, and then there is the Terry Jones case, the burning of the Quran, that he went through with, with probably the certain knowledge that it would lead to violence and death somewhere among radical Islamists elsewhere in the world. Does that change the sanctity of free speech at all?

GEOFFREY STONE: Well, it certainly raises the stakes because now the harm that’s caused by the speech is much graver – death. So the question is, well, can you suppress speech, can you punish speech because it offends people to the point where they actually go out and kill somebody? There the argument is much more difficult, of course. But, having said that, the same slippery slope problem exists. So let's suppose that we were to hold that the reverend could be punished because the speech led to the death of individuals in Afghanistan. And now let's suppose that instead of that, that the City of New York prohibits the construction of a mosque near the site of, of 9/11, and radical Islamicists are furious at the discrimination against Islam and they go out and they kill people, in protest. Does that mean that we have to allow the mosque? Or suppose that someone criticizes, in a speech, Islam as a violent religion and Jihadists somewhere in the world go out and they kill Americans in protest to that. Basically what happens then is you encourage those who would suppress speech in the United States to exercise a power of censorship here by engaging in violence there. And it’s called the heckler’s veto in First Amendment doctrine, and once you allow the heckler's veto, once you allow people to essentially cause you to silence speech because of their willingness to engage in criminal conduct, then you've basically turned over the First Amendment to other people.

BOB GARFIELD: Although, in some respects, we do go down that road, do we not? I mean, freedom of expression is not absolute in this country, and there have been attempts by the government, particularly during wartime, to suppress speech. Can you give me some examples?

GEOFFREY STONE: Sure. I mean, there – there’s been a long history in the United States of government efforts, in particular in time of war, to restrict speech. For example, in World War I, the government made it a crime for any person to criticize the President, the Congress, the war, the flag, the military, the uniform of the military, the draft, and individuals were sentenced to prison terms of 10 to 20 years. And the rationale was that such criticism would undermine morale in the United States. It would strengthen the will of the enemy. And the Supreme Court initially upheld those prosecutions. And over time, what’s happened in the United States is we went from what we thought was common sense to an understanding that common sense with respect to free speech, in particular, is not a very sensible way of going about defining the scope of the rights.

BOB GARFIELD: And hence, the genius of the Founders. The First Amendment is constructed on a principle that may intellectually scan perfectly, as you've just elucidated but just, you know, in many ways just feels so wrong.

GEOFFREY STONE: Well, the genius really is not just of the Founders. It’s of the Supreme Court, because the Founders themselves didn't know exactly what they meant by the First Amendment. It’s important to remember that the Sedition Act of 1798, which was enacted less than a decade after the First Amendment was adopted, made it a crime for any person to criticize the President or the government of the United States. And many of those people involved in the crafting of the First Amendment supported the constitutionality of the Sedition Act. So even the framers didn't really know what the constitutional guarantee of free speech necessarily meant. That’s something that it took us 200 years of living with it and trying to figure out, from trial and error, how to make it work that we finally thus far seem to have figured out pretty well. And the way you can see that progress is, you know, during World War I, as I said, people who criticized the war were put in jail for 10 to 20 years. During the Vietnam War or during the post-9/11 period we didn't put people in jail for criticizing the war. We came to understand that free speech and American politics and self-governance demanded that individuals have the freedom to criticize the government, to criticize the war, to criticize our policies, even though it might have negative consequences, because otherwise we would be crippling the very self-governance that this society is meant to preserve.

BOB GARFIELD: Geoffrey, thank you very much.

GEOFFREY STONE: My pleasure, as always.

BOB GARFIELD: Geoff Stone is a law professor at the University of Chicago.