(CNN)It's easy to be anxious about the threat posed by the Islamic State of Iraq and Syria. After all, this is a brutal organization that not only kills but seems to revel in doing so in ways designed to shock the world -- from the beheadings of journalists to burning a Jordanian pilot alive. Such moves are part of this murky group's propaganda and its deliberate efforts to manipulate information. So what can and should we make of the organization? I explore the issue in depth in a special airing Sunday night. And although it's important to start with the caveat that ISIS is indeed trying to scare and confuse us, I took away some tentative lessons from speaking with the people who have traveled inside the minds of ISIS. First, ISIS is clearly about religion -- its version of radical Islam -- but it is also about power. There is increasing evidence that the military backbone of ISIS is made up not by a group of Islamic zealots, but rather high-ranking officers from Saddam Hussein's army -- Baathists who were at least ostensibly secular. An internal ISIS report detailing its organizational structure was reported on last week in the German weekly Der Spiegel. That report describes a group that uses its religious ideology as a recruiting and governing philosophy, much like communism. But underneath it, much like communism, is simply a drive for control, a lust for power. Next, ISIS presents itself as a global organization, but it has thrived because of a local cause. The group has gained territory, cash and recruits primarily because of the rage and rebellion of the Sunnis of Iraq and Syria, who believe they must fight the Shiites to secure their own survival and strength. The reality is that that Sunni cause is going to endure for some time. The United States has been successful in its tactical battles against ISIS and has managed to push the group back from many of its gains in Iraq. But the Sunnis of the region will remain in rebellion and the Sunni-dominated areas will remain in turmoil -- chaos that ISIS will be able to capitalize on this chaos. In the long run, ISIS might very well find that its greatest foes lie within its so-called Caliphate. The few reports that are emerging from areas controlled by ISIS suggest that, unsurprisingly, people do not like living under a brutal, theocratic dictatorship. They live in fear, and even those who chose it as an alternative to Shiite rule are growing disenchanted. In this respect, ISIS is like other radical Islamic groups, such as the Taliban -- they have an allure in the abstract, but once they are actually governing in their medieval, barbarous manner, the allure fades and the disenchantment builds. The result is ever-increasing repression. Remember, no one has ever voted ISIS into power anywhere. The group simply slaughters its way to control. Of course, one of the big questions has been: Is ISIS a threat to the West? The group's leaders declare that it is. But their ambitions appear to be mostly centered on their Arab enemies, on building a caliphate in Iraq and Syria. They understand, of course, that to be Terror Group No. 1, they must battle the country that is the world's No. 1 power -- the United States. With that in mind, they seek such a confrontation and hope that the United States will come to the Middle East and fight them on their terms, on their terrain. Still, while they are opportunists, and they ask and hope that their followers act in America, their main focus is not to come here -- they want Americans to go there. Yet no matter how one rates the level of the threat ISIS poses, the group has changed the nature of terror. The leaders of ISIS have recognized that above all, they are a messaging machine, which in turn becomes a recruitment machine. This means that the key is not what happens on the ground, but on the airwaves and in the bits and bytes of the Internet. And ISIS does this better than anyone before them because while their gruesome videos would seem a repulsive turn-off -- and are to most -- they still work on the web. The shock and awe they produce makes them go viral, and thus are seen by tens of millions. That ensures that these videos attract those utterly alienated young men -- a few thousand among the world's 1.6 billion Muslims -- who seek revenge, glory and gore. Unfortunately, as long as those young Muslim men, scattered across the globe, are attracted to ISIS and stream to its cause, the group presents the world with a danger that is impossible to fully assess but is one that grows by the month.
Fareed Zakaria: ISIS has thrived because of a local Sunni cause in Syria and Iraq .
Leaders of ISIS have recognized they are a messaging machine, he says .