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As the United States prepares to step up its campaign against ISIS, a new CIA report shows the radical Sunni group has at least double (and possibly triple) the number of fighters in its ranks than had previously been speculated.

Two days ago, officials testified ISIS had 10k members. After the speech, that figure tripled. — Matt Apuzzo (@mattapuzzo) September 12, 2014

The new CIA intelligence assessment was released late on Thursday in which information was culled from various reports across the summer, which as the AP reports, "estimates that the Islamic State group can muster between 20,000 and 31,500 fighters across Iraq and Syria, up from a previous figure of 10,000."

Writing in the New Republic, Graeme Wood compellingly classifies the three different types of ISIS fighters, including a cooperative of Western poseurs (Psychopaths) and committed zealots (True Believers). If there's any silver lining to be had, it's that what Wood calls the largest contingent of ISIS fighters doesn't seem particularly committed to the cause.

Call them the Sunni Pragmatists. These people include Iraqi tribal sheikhs, whose allegiance to ISIS originates not in a cultish death wish but in a desire to win security and well-being, and who seem to be using the Psychopaths and the True Believers as convenient allies. From ISIS, the Pragmatists get a way to punish Baghdad for its long neglect of Sunni regions."

Nevertheless, that new number is certainly alarming.

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