Foley beheading reveals barbarity at heart of Islamic State [Commentary]

Hollywood has come up with some fearsome swarms of monstrous villains -- think of the orcs in "The Hobbit" or the zombies in "World War Z" -- but those computer-generated creatures are nothing compared to the all-too-real swarm of monsters that have rallied to the black banner of the Islamic State in Iraq and Syria.

ISIS (or ISIL, the alternative version of the name that substitutes the broader geographic term, Levant, for Syria) may be the most despicable band of barbarians to plague the world since the Khmer Rouge finished stacking up the skulls of their victims in Cambodia 35 years ago. Emerging from the chaos of the Syrian civil war, ISIS militants have swept across the Iraqi desert and seized control in much of that country over the last two months.

They are not the first armed force to bring havoc to that tortured land, but they are arguably the worst. Driven by a fanatical allegiance to an extremist form ofSunni Islam, ISIS shock troops have carried out crucifixions and beheadings, raped women, abused children and sold both into slavery. Whenever they encounter someone who does not share their perverse version of Islam, they offer a choice: convert or die.

On Tuesday of last week, a video surfaced showing a masked executioner beheading American journalist James Foley. The executioner -- probably one of many Islamic radicals from Europe and the U.S. who have joined the ISIS army -- spoke with a British accent. On the video, he said Foley's brutal murder was in retaliation for American airstrikes that have stopped ISIS from overrunning Iraq's Kurdish region. Wednesday, U.S. officials revealed that an unsuccessful Special Forces mission to free Foley and other Americans held by the militants in Syria was attempted earlier this summer. ISIS now is threatening to execute more of those American captives.

There is something especially gruesome about a beheading. It is hard to imagine how one human being can perpetrate such a grisly act on another, but the ISIS horde has proven capable of any atrocity. In a region that has seen decades of war, authoritarian rule and sectarian violence, the Islamic State militants have found a way to plumb even deeper depths of savagery. There appears to be no limit to the horrific things they will do to build their new caliphate.

Americans thought they were done with Iraq after 10 years of a misguided war and frustrating occupation. It seemed time to let the factions sort out their own problems. But ISIS is so bad - for once, a comparison to the Nazis is not an exaggeration - that the United States cannot leave the job of opposing them to someone else.

Angry and grim, President Obama on Wednesday expressed outrage over Foley's murder. He pledged to continue strikes against the "cancer" of ISIS, saying, "We will be vigilant and we will be relentless."

The president rejected the idea that this army of Sunni extremists represents a legitimate form of Islam. "Their victims are overwhelmingly Muslim, and no faith teaches people to massacre innocents," Obama said. "No just God would stand for what they did yesterday, and for what they do every single day."

And, despite war weariness, past mistakes and the messy complications of engaging with the unending conflicts of theMiddle East, no country that claims to champion human rights and freedom of thought can refuse to stand against such a pitiless, malevolent force.

Two-time Pulitzer Prize winner David Horsey is a political commentator for the Los Angeles Times. Go tolatimes.com/news/politics/topoftheticket/ to see more of his work.