Terrorists Strike Again: ISIS Murders British Aid Worker

Turning its campaign of videotaped terror toward Washington’s primary battlefield ally, the Islamic State released a video showing the beheading of British aid worker David Haines and threatening to kill another British hostage.

The murder makes Haines the third Western captive to be killed by the militants in the weeks since American warplanes first began bombing targets belonging to the Islamic State, the armed group that controls broad swaths of Iraq and Syria.

It comes just days after Obama gave a prime-time speech to the nation outlining his strategy for countering the militants. A centerpiece of that new approach is the construction of a broad coalition of nations willing to take part in the various aspects of the anti-ISIS campaign. Britain has been the only country beyond the United States willing to consider airstrikes on targets inside Iraq, and Haines’s murderer said the aid worker, a father of two, was being killed in response.

"Your evil alliance with America, which continues to strike the Muslims of Iraq and most recently bombed the Haditha dam, will only accelerate your destruction and claim the role of the obedient lap dog," the masked militant, who sounds like the man who killed American journalists James Foley and Steven Sotloff, says in the video. "[British Prime Minister David Cameron will only drag you and your people into another bloody and unwinnable war."

The video’s impact on British public opinion, which has been ambivalent about getting involved in the fight against the Islamic State, is hard to predict. In the U.S., public support for an armed campaign against the Islamic State skyrocketed after the murders of the two American journalists. It may do the same in Britain, but it may also strengthen those arguing that Britain risks paying a high price for its new alliance with the U.S. in the anti-ISIS fight.

Haines had been held up to the camera and threatened at the end of the video of the Sotloff killing. The newest one ends with a masked militant holding another hostage, this one identified as British citizen Alan Henning.

Cameron, in a tweet, called the murder "an act of pure evil" and promised to hunt down those responsible. Earlier this month, Cameron’s government said it dispatched British commandos to try to rescue an unnamed British citizen but failed. It’s not clear if that was an attempt to free Haines, 44, who was captured inside Syria.

The White House, in a statement Saturday night, said it "strongly condemns the barbaric murder of U.K. citizen David Haines."

"Our hearts go out to the family of Mr. Haines and to the people of the United Kingdom," the statement read. "The United States stands shoulder-to-shoulder tonight with our close friend and ally in grief and resolve."