As anti-American protests erupt in the Muslim world, the United States is powerless to act against those who incited the violence due to the freedoms enshrined in its cherished constitution.
The catalyst for the conflagration, which is spreading across the Middle East and North Africa, was a privately-made film denigrating the Prophet Mohammed linked to evangelical and Coptic Christians in the United States.
The suspected producer is Nakoula Basseley Nakoula, a 55-year-old Copt living in California. It was promoted on the websites of two other Americans, extremist Christian pastor Terry Jones and another Copt, Washington-based lawyer Morris Sadek.
"I know it is hard for some people to understand why the United States cannot or does not just prevent these kinds of reprehensible videos from ever seeing the light of day," secretary of state Hillary Clinton said on Thursday.
"Now, I would note that in today's world with today's technologies, that is impossible. But even if it were possible, our country does have a long tradition of free expression which is enshrined in our constitution and our law, and we do not stop individual citizens from expressing their views no matter how distasteful they may be."
The justice department refused to be drawn on what avenues it may be pursuing to punish Nakoula and others, but experts said there was nothing they could do to restrict people from exercising their constitutional rights.
"The US government is powerless in the specific sense that the constitution allows Americans to speak this way without fear of being thrown in prison because some people find what they say blasphemous," professor Eugene Volokh, an expert on free speech law, told AFP.
File photo of US ambassador to Libya Chris Stevens who was killed in a rocket attack in Benghazi. (AFP photo)
The First Amendment to the US constitution states that: "Congress shall make no law... abridging the freedom of speech."
In the 1969 Brandenburg v Ohio case, the Supreme Court held that the government cannot punish inflammatory speech unless it is directed to inciting, and likely to incite, "imminent lawless action."
The so-called Brandenburg test -- of intent, imminence, and likelihood -- holds sway today, and explains why the US government is powerless to punish the filmmakers or prevent a repeat of such an episode.
At a campaign event in Colorado on Thursday, US President Barack Obama said "no act of terror" would "dim the light of the values that we proudly present to the rest of the world."
But "Innocence of Muslims," an amateurish production with bad dubbing and false beards and a cast that thought it was working on something entirely different, has caused death and destruction and placed fresh scrutiny on those values.
Volokh, who teaches at the University of California, Los Angeles (UCLA), said, like it or not, the First Amendment protects the freedom of speech for everyone, crass and high-minded alike.
"That's true with Salman Rushdie, that's true with the producers of South Park. That's true with these people," he told AFP.
"Even advocacy of violence is protected, and this isn't advocacy of violence, this is just parody of and criticism of religion."
In the Internet age, any meaningful change would mean a total ban on any speech that might incite fanatical Muslims to react with murder.
While Nakoula enjoys police protection at his home in the Los Angeles suburbs, the FBI is probing the deaths of four American nationals, including the country's envoy to Libya, killed during protests over the film.
The circumstances surrounding the storming of the Benghazi consulate on Tuesday are murky and US authorities believe Al-Qaeda-linked extremists may have planned the attack under the cover of the protests.
But the demonstrations that started hours earlier in Cairo and have now spread to much of the Middle East and North Africa are largely over the film, a trailer of which was dubbed into Arabic and promoted on the Internet.
Steve Klein, an evangelical Christian who admits to being a consultant on the project, said he did not feel responsible for the American deaths.
"In this case with the ambassador, I did not kill these people. It is they who pulled the trigger. It is they who murdered the ambassador," he told CNN.
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