(CNN) -- President Obama authorized the killing of an American citizen because he had declared war on the United States and encouraged others to bring harm to America. Whatever Anwar al-Awlaki's wrongs -- and there were many -- when America kills its own without a trial, it not only demeans itself but it hands over a propaganda victory to its enemies.
Ayman al-Zawahiri, al Qaeda's leader since the death of Osama bin Laden, will chide this great country again for abandoning its values and principles. The White House's authorization of this killing also tells American Muslims that a precedent has been set by their government to kill American citizens abroad without trial if they oppose their country.
This cannot be right -- and is counterproductive to defeating terrorism in the long term because it demolishes the very values that America stands for: the rule of law and trial by jury.
It is abandoning these very same principles of human dignity, underpinned by free and fair trials that led to al-Awlaki's decisive shift after being released from a Yemeni prison in 2007: From being anti-American rabble-rouser, he went to advocating direct violence against the United States. Prison experiences in the Arab world -- being arrested and detained without legal representation and exposed to the worst forms of torture at the hands of fellow Muslims -- change nonviolent extremists to violent extremists. Al-Awlaki's transformation from extremism to violence comes in this context.
His alleged links to 9/11 terrorists were not as significant as some argue. If he was known to be involved in the 9/11 attacks, why was he a guest of the Pentagon, of all places, in 2002?
Al-Awlaki is not alone. Before him, al-Zawahiri was tortured in Egyptian prisons, and during his trial in 1982, he addressed a gallery of Western journalists in English and declared, "So where is democracy? Where is freedom? Where is human rights? Where is justice? We will never forget!"
Without a doubt, al-Awlaki and al-Zawahiri were already radicalized before prison, but the tipping point toward violence came with their prison experiences. And before al-Zawahiri, the intellectual framework for al-Qaeda's destructive worldview was put in place by Syed Qutb in Mazra Tora in prison in Nasser's Egypt. Again, it was torture and the absence of humane treatment that led to Qutb declaring war on the Egyptian government. Qutb's prison writings have inspired every jihadist movement around the globe.
This same movement sees al-Awlaki as a lightweight, not least because he never set foot on the battlefield and his scholarly credentials are open to question. In Egypt or Pakistan, al-Awlaki is not well-known. Little wonder, then, that Al Jazeera Arabic is not as excited by al-Awlaki's killing as Western media outlets.
Al-Awlaki was important among Muslims in the West -- from Yemen, he used the Internet to reach this constituency. But even before the launch of his blog in 2008, al-Awlaki was popular among Muslims in England, Canada and America because of his audiotapes about the history of early Muslim personalities. These tapes were, and many still are, in circulation in mosques and bookshops.
Al-Awlaki could have been discredited before his prison experiences or, now, his perceived martyrdom. By killing al-Awlaki, his message gains new life as words from an American Muslim martyr, the first to join the iconography of underground Muslim culture since Malcolm X.
An easier, cheaper and more effective way of discrediting al-Awlaki and countering his message would have been to disclose his three arrests for the solicitation of prostitutes in San Diego and the Washington, D.C., area between 1996 and 1997. He had even pleaded guilty to the 1997 charge, and was subsequently sentenced to three years' probation and a fine. Among his socially conservative Muslim following in Europe and America, immediately after 9/11, such information would have been dynamite.
The United States cannot kill its way out of terrorism. Just as with the Cold War, the challenge from Islamist extremism and jihadist violence urgently needs a cultural, intellectual and informational response. Violence breeds more violence and, in this case, literally creates martyrs out of al Qaeda's murderers.
The opinions expressed in this commentary are solely those of Ed Husain.