(CNN) -- America was rightly shocked by the brutal, videotaped murder of American journalist James Foley. But we should not have been surprised. The Islamic State, as the jihadist group calls itself, has murdered, raped and savaged its way across borders in the Mideast and into the headlines as the latest terrorist foe from the region. Foley's murder not only gives terrorist stature to ISIS but also, if it draws U.S. ground troops into the fight, will have given ISIS a recruiting bonanza. So the U.S. response requires, not just a set of airstrikes in revenge, but serious strategic calculation.
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Wesley Clark: U.S. must respond to ISIS threat, but with coordinated regional response
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He says U.S. can support Islamic friends in region threatened by ISIS, but can't fight their war
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He says ISIS has sights on states like Jordan, Lebanon; it could well seize Saudi Arabia
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Clark: U.S. involvement only helps recruit jihadists. Mideast nations facing their moment of truth
For @placeholder, this time, there's no safety in underwriting the services of others from outside the region.