Since the video showing the execution of American journalist James Foley, the U.S. has conducted more than a dozen airstrikes against the Islamic State in northern Iraq.
In the video, the man who kills Foley says the execution is retribution for the airstrikes and he threatens to kill another American hostage if they are not halted.
So what does this mean for the conflict going forward, and does the Islamic State pose a direct threat to the West? Britain says hundreds of its citizens are fighting with the militants, and officials are concerned they might return to the U.K. and carry out terrorist acts.
Bruce Hoffman, director of the Center for Peace and Security Studies at Georgetown University, tells Here & Now's Meghna Chakrabarti that the Islamic State delivered a clear message with the execution of James Foley.
"They are not intimidated, they are not going to give in, and that they believe they have a way of inflicting pain on us," Hoffman said.
This segment aired on August 21, 2014.