Iraq's Insurgency After Zarqawi - Council on Foreign Relations -
Council on Foreign Relations: World - Jun 9, 2006 -
A decent article about the remainder of the Iraqi insurgents (the International Crisis Group's report, "In their own words" (Feb 2006), is more in depth, but less immediately digestable due to the details about each of the many insurgent groups) that concludes that the Iraqi Sunni insurgents won't be satisfied until perceived humiliations (by Americans, of the loss of their control/country, etc) have been addressed. I concur.
Khalayleh's influence was and legacy is to show that an independent cell-structure could carry out objectives that were tangentially related to Al Qaeda and be successful and (grudgingly) accepted by Al Qaeda. Madrid, London, and Tornoto all owe their origins and inspiration from the independency of Zarqawi. His priority was sewing dissent by attack Shia and destabilizing the region (for him, Iraq and Jordan were more important than America, Saudi, or Europe or the goal of the Caliphate), unlike "orthodox" Al Qaeda ideology.
For Iraq, Zaraqwi's death means a cooling of Al Qaeda influence and a chance to heal the Shia-Sunni rift. The foreign-born jihadists in Iraq will experience a marked decline (more than they were already experiencing) now that Zarqawi isn't available to continue the PR and impose his ideological and tactical differences on Iraq. It won't matter if it's Abu Ayyub al Masri (an Egyptian that Zarqawi picked to be his successor) or Abu Abdel Rahaman al-Iraqi (a Baghdad native previously from a different insurgent group who is AQI's 2nd in command) who takes over Al Qaeda in Iraq, the Iraqi government's continued stability should now be getting closer to being enough to contain their insurgency.
As mentioned above, the broad view of the Iraqi insurgent composition doesn't help with minor course changes, but gives a general handle on what the insurgents are fighting for (and against). The article references Ahmed Hashim's Insurgency and Counter-Insurgency in Iraq which I'm currently reading and hopefully I'll make commentary or at least a summary.
For the rest of the world, though, it's Zarqawi's life that'll give hope for the broader, violent Salafist movement - whether in line with Al Qaeda's goals or not. I expect more "copy-cat school shootings" - half-baked, but baking, nonetheless - like London and Toronto to be the commemerative reactions: DIY "Al Qaeda," and if you're good enough, you can use the brand name. Further, because of this, the image of Islam will continue to be denigrated by western governments and populaces, reinforcing an anti-muslim view that perpetuates both the War on Terror and the rationales for resistance.