Ahmed Rashid in The New York Review of Books:
In the days since the Islamic State in Iraq and Syria (ISIS) took control of much of northern Iraq, Western leaders and analysts have expressed alarm at what they have called a powerful new form of jihadism. Some have likened ISIS to a new al-Qaeda. Both assessments are wrong. In its rapid advance toward Baghdad, ISIS has already eliminated national boundaries between Iraq and Syria, captured significant arms and weapons caches, caused a spike in global oil prices, reinvigorated ethnic and sectarian conflict across the Arab world, and given Islamic extremism a dramatic new source of appeal among many young Muslims. On June 30, the first day of Ramadan, ISIS also declared that it was reestablishing the “Caliphate,” long an aspiration of other jihadist groups.
Yet despite these accomplishments, ISIS may not be as unusual as it has been described. Nor does it seem primarily interested in global jihad. In many ways, what the group is doing to Syria and Iraq resembles what the Taliban did in Afghanistan and Pakistan in the early 1990s. Like the Taliban, ISIS’s war so far has been about conquering territory rather than launching an al-Qaeda-style global jihad or issuing fatwas to bomb New York or London. Although it has attracted some three thousand foreigners to fight for it, ISIS’s real war is with fellow Muslims, and in particular Shias, against whom it has called for a genocidal campaign. Just as the Taliban changed the contours of Islam in south and central Asia so ISIS intends to do the same in the Middle East. ISIS is also seeking territorial control of the central Middle East region. There are several instructive parallels between the two groups. The hardcore forces of ISIS probably number fewer than 10,000 trained fighters; the Taliban never numbered more than 25,000 men—even at the height of the US surge when there were over 150,000 Western troops in Afghanistan and twice that many Afghan soldiers.