The propagandists of the Islamic State must have imagined that their brutal video of the beheading of journalist James Foley would intimidate and terrorize the world. But people aren't built that way, not in Muslim countries or anywhere else. When they see sadistic, uncivilized behavior, they are disgusted - and angry.

President Obama spoke with special precision and moral clarity in reacting to the video's release Wednesday. The Islamic State, he said, "speaks for no religion. Their victims are overwhelmingly Muslim, and no faith teaches people to massacre innocents. No just God would stand for what they did yesterday, and for what they do every single day."

The videotaped beheading was a sign of the Islamic State's weakness, not its strength.

"People like this ultimately fail," Obama explained. "They fail, because the future is won by those who build and not destroy."

He spoke, as a president must, about the consequences of killing U.S. civilians: "We will be vigilant and we will be relentless. When people harm Americans, anywhere, we do what's necessary to see that justice is done."

The life and death of Osama bin Laden illustrate why the terrorist strategy is destined to fail - if civilized nations maintain their will. Obama authorized the mission that pursued the al-Qaida leader to his lair in Abbottabad, Pakistan. But in the months before his death, bin Laden knew he had failed. Documents taken from his hideout show that in his final days, bin Laden was haunted by the mistakes al-Qaida had made. The organization's wanton killing had appalled and alienated Muslims, to the point that bin Laden wondered if the group should rebrand itself as a less toxic force. He even suggested 10 alternative names that might sound better to the world's ears.

Bin Laden reflected in a draft letter about "miscalculations" and "unnecessary civilian casualties" that were hurting the jihadist cause. "Making these mistakes is a great issue," he said, noting that taking "Muslim blood" had resulted in "the alienation of most of the nation (of Islam)." Local al-Qaida leaders should "apologize and be held responsible for what happened."

This week's macabre executioner, robed in black, traces his jihadist lineage to the very people bin Laden was condemning, the leadership of al-Qaida in Iraq. Whether this successor is called ISIL, or ISIS, or the Islamic State - it has chosen to debase itself with the most extreme and bloodthirsty version of Muslim revolt. Its actions and boasts are a kind of jihadist fantasy, celebrating the pornographic violence of religious killing with beheadings and crucifixions and genocidal assaults on Shiite Muslims, Yazidis, Christians and dissenting Sunnis.

We can see evil through the eye slits of the ski mask worn by Foley's killer. But stopping that evil is a harder task. As America has witnessed over the past decade, the obsession to counter terrorism can drag a country into unwinnable wars and immoral acts.

For months, Obama has been struggling with the question of how to get it right this time - how to contain and eventually eradicate the Islamic State without making America the Muslim world's enemy. Obama's voice could have been clearer and more emphatic, early on, but I think the basic course of his policy has been correct. He has moved strategically, step by step, gathering the tools that will be needed to confront this malignancy.

Consider how this policy has come together: Knowing that Iraqis must lead the fight against the killers in their midst, Obama refused American air support until Iraqis had endorsed a more inclusive government. Recognizing that the mission should have limited initial goals, he focused on rescuing the Yazidis trapped atop Mount Sinjar. Calculating that Iraqi Kurdistan would be a crucial platform for U.S. projection of power, he pledged to defend Irbil.

A crucial turn was the campaign to win back Mosul Dam. Understanding that jihadist control of the massive dam amounted to a dagger at Iraq's throat, Obama said on Aug. 9, "there's key infrastructure inside of Iraq that we have to be concerned about." Few noticed. This month, 57 of the 90 U.S. airstrikes have been in support of Iraqi forces at Mosul Dam.

Knowing that the jihadists were holding American journalists hostage, Obama ordered a raid earlier this summer to free them. This bold action failed, but it was correct. Even though he knew that European governments had paid huge ransoms to free their hostages, Obama refused. Those were difficult but sound decisions, and a principled start to a long campaign against brutal killers.