If President Barack Obama was serious last week when he addressed the United Nations, then he just quietly declared war on the First Amendment. If he wasn't serious, then he is pandering to murderous mobs who demanded that he denounce an obscure YouTube video critical of their faith.

The New York Times portrayed Obama’s remarks as a strong defense of free speech and a challenge to Arab leaders to reform. If only that were true.

Looking at the actual words Obama used reveals what could be called "The Obama Doctrine”-- where the U.S. Constitution does not permit the president to restrict speech before it is spoken, the president will punish speech, after the fact, by marginalizing the speaker.

“[I]t is the obligation of all leaders, in all countries, to speak out forcefully against violence and extremism. It is time to marginalize those who -- even when not directly resorting to violence -- use hatred … as a central organizing principle of politics,” Obama said.

Later in his speech, Obama offered an example of those whose opinions should be marginalized: “The future must not belong to those who slander the prophet of Islam. Yet to be credible, those who condemn that slander must also condemn the hate we see in the images of Jesus Christ that are desecrated...”

"Slander" is speech. "Hate" usually takes the form of speech too. Is Obama calling on world leaders to join him in ridiculing nonviolent people whose speech he does not like? Or by “marginalization” does he mean something worse than tough words from the bully pulpit?

Obama’s new doctrine is frightening in two senses. His call to “marginalize” those who "slander" or "hate" encourages the autocrats of Iran, Syria and other regimes to punish dissidents while also threatening to shrink the free speech rights of Americans.

Let’s be honest: The only way to police hatred is to police speech. Governments cannot read hearts or minds, but they can read blogs, tweets and texts, and punish what they find disagreeable there. This is what Obama’s “marginalizing” of “hatred” looks like.

At first, governments ban only a few “hateful” words. But we know where this leads. Every time such broad power is given to the powerful, they determine that everything critical of their power is “hate” and therefore banned. Over time, free speech is lost. U.S. presidents and judges have never bestowed this power upon themselves, nor can they under U.S. law, and this is why the country remains free.

Obama’s words signal a sharp departure [from the status quo]. For generations, presidents have defended the rights of individuals to say unpopular things as long as they avoided imminent violence. Obama told the UN that even nonviolent speech -- if he considers it hateful -- should be punished through government-sponsored marginalization. This rewrites two centuries of First Amendment law.

Has an American president ever called for government action, at home and abroad, to “marginalize” peaceful, nonviolent citizens whose opinions he disfavors? On the subject of religion?

Bad speech should be countered by good speech, and that is the job of the citizens, not the government. The government may not pick winners and losers in the marketplace of ideas.

In America, politicians cannot punish free speech. This is the freedom that makes Bill Maher's "Politically Incorrect" funny and it is the freedom that keeps the artists who created the "Da Vinci Code" walking free. Does the president really want to take that away?

Americans were left to wonder last July when the president's assistant attorney general for civil rights, Tom Perez, seemed to have great difficulty articulating the administration's position on free speech before a congressional oversight panel. Repeatedly, he struggled to avoid answering the question: "Will you tell us that this administration's Department of Justice will never entertain or advance a proposal to criminalize speech against any religion?"

Americans have no constitutional right to not be offended. Neither does the president, nor murderous, rioting mobs in Cairo. Offending others is an American tradition. From the Boston Tea Party to today’s American rap music scene, offense is one way we communicate.

Offending people’s religious sensibilities is no exception. When the U.S. Supreme Court struck down government efforts to censor a film offensive to Christians in the 1952 case of Burstyn v. Wilson, the high court found that “the state has no legitimate interest in protecting any or all religions from views distasteful to them.… It is not the business of government in our nation to suppress real or imagined attacks upon a particular religious doctrine, whether they appear in publications, speeches or motion pictures.”

Likewise, in the 1992 case of R.A.V. v. City of St. Paul, the Supreme Court struck down a law that prohibited speech or symbolic expression that "arouses anger, alarm or resentment in others on the basis of race, color, creed, religion or gender," because the restriction on speech was impermissibly content-based and viewpoint-based.

The constitutional guarantee of free speech extends to all viewpoints. There is no exception for “hate speech,” whatever that broad, vague term might mean. As the Supreme Court made clear in a 1974 case of Gertz v. Robert Welch, Inc., “Under the First Amendment there is no such thing as a false idea. However pernicious an opinion may seem, we depend for its correction not on the conscience of judges and juries but on the competition of other ideas.”

In short, the Obama Doctrine is likely unconstitutional.

The president may argue that existing law does not bar his marginalization doctrine, because the laws in these cases were either complete restrictions of speech or something other than his idea of permitting the speech but marginalizing (punishing) the speaker. His proposal merely discourages undesired speech. First Amendment lawyers call this “chilling” free speech. That, too, is illegal.

The Obama Doctrine is not spontaneous or new. Secretary of State Hillary Clinton foreshadowed it in a July 2011 speech before the Organization of Islamic Cooperation, or OIC, an international organization comprised of all Muslim-majority nations. Clinton promised the OIC that the U.S. would endorse a government campaign using “old-fashioned techniques of peer pressure and shaming” against citizens who do or say things that the government "abhor[s]." Clinton’s words were warmly welcomed by the OIC, which had been campaigning to limit free speech in Western democracies for more than a decade. This most recent OIC speech-restriction campaign is called the “Istanbul Process,” and Hillary Clinton is a proponent.

The culmination of the Istanbul Process is U.N. Resolution 16/18, which aims to enlist government actors to "counter offensive expression" by chastening any speech critical of religion. In practice, U.N. Resolution 16/18 chills speech critical of Islam -- with the offense being defined by the offended, not the black letter of the law. The Obama Doctrine is its American manifestation.

The Obama Doctrine is dangerous and unfit for a free people. Congress should demand that the president define marginalization to learn if his plan extends even beyond the use of the bully pulpit. Besides the president denouncing the controversial YouTube filmmaker was the horror of federal agents outing his name and whereabouts to the press. Using publicity to marginalize the filmmaker -- in the face of death threats to him and his family -- exposed the filmmaker to more than just shame. Is this the Obama Doctrine at work? Leaving artists to fear that politically incorrect speech will result in a similar “outing” creates a climate of intimidation.

How will America respond to this gradual erosion of free speech? We must resist the temptation to condone affronts to the First Amendment simply because we dislike the message of the speaker. The traditional American remedy is to demand that the courts force the government to respect free speech, but this process becomes more difficult when the chief executive does an end run around the American people. Obama did not present his dangerous new doctrine to the American people or the people’s representatives in Congress. Instead, he announced it at the U.N. to an audience of the world’s most oppressive regimes.

Maybe they can understand him better.

Publius is the pen name of a civil rights lawyer and veteran Capitol Hill insider.