Updated

Arizona Sen. John McCain on Thursday called President Obama's remarks on the execution of American journalist James Foley "moving" -- but also said his policy on the Islamic State terror group is failing.

"He said we have to contain ISIS. We don't have to contain ISIS. We have to defeat ISIS, and we have to do whatever is necessary," the Republican lawmaker said on Fox News' "America's Newsroom."

"Failures of policies have consequences, and we're paying [for] those consequences in enormous cost of human blood. It's a debacle, and he still doesn't get it."

McCain called the growing chaos in Iraq "predictable" after Obama's "huge mistake" of not leaving a residual U.S. force behind.

"This didn't have to happen," he said. "This is an abject failure."

McCain said he wants to see a "comprehensive strategy" explained to the American people with the goal of defeating ISIS "wherever they are."

"It's more than pinprick airstrikes," he said. "We're gonna need more boots on the ground -- and that does not mean combat troops -- but it does mean a significant increase."

McCain hopes Foley's death will send a "strong message" to Americans that ISIS could stage an attack on U.S. soil. "They will be coming to America unless we stop them," he warned.