Al Qaeda, its affiliates and inspired non-affiliates continue to be popular in the Muslim world, united in part by their rejection of U.S. military forces in Iraq and Afghanistan and by material benefits they gain by adhering to Osama bin Laden’s ideology, says a new report authored by two analysts at the Center for Strategic and International Studies (CSIS).

While there has been less public support for certain tactics of al Qaeda and Associated Movements (AQAM), such as suicide bombings, and even increased criticism within certain Muslim circles over the killing and maiming of Muslim civilians, the three-tiered group has been growing “organically,” say Rick “Ozzie” Nelson and Thomas Sanderson in their CSIS report, A Threat Transformed: Al Qaeda And Associated Movements In 2011. The report was released yesterday.

For one, AQAM’s goals such as keeping Western values out of the Muslim world, withdrawing U.S. forces from Islamic countries and ending U.S. support for unpopular governments such as Egypt’s are backed by majorities or near-majorities of respondents in Egypt, Indonesia, Pakistan and Morocco, according to a 2009 Univ. of Maryland poll the report’s authors cite.

“For a small fringe, the benefit of achieving these goals remains paramount, even if it means supporting AQAM’s murderous and increasingly unpopular approach,” says the report.

“More importantly, though, is the growing resonance of bin Laden’s ideology in the post-9/11 worlds,” says the report. It says that the presence of U.S. forces in majority Muslim countries “underscores” AQAM’s argument that the West is at war with Islam.

Nelson and Sanderson also say that material benefits such as fundraising and recruiting associated for aligning with the core al Qaeda leadership, as well as the prestige it brings, also may drive the expansion of AQAM.

The report divides AQAM into three tiers, with the first being the original core of al Qaeda, including bin Laden and his immediate followers and commanders. This core became “degraded” following the U.S. invasion of Afghanistan and arrests by others of key al Qaeda leaders, the report says.

Still the fact that senior al Qaeda leaders remain at-large, including bin Laden, means they are “potent strategic and symbolic figures within AQAM,” the report says.

Through the 2000s other Islamic terrorist groups grew that were formally and informally affiliated with al Qaeda, the report says. The growth of this second tier meant that the terrorist threat could be thought of as a movement, hence AQAM, it says.

The third tier consists of individuals and cells that are not affiliated with al Qaeda but are inspired by, and in some cases guided by, AQAM, the report says. One example is failed Times Square bomber Faisal Shahzad, who traveled from the U.S. to Pakistan for training, it says.

The new report is part of a year-long study being done by the CSIS researchers aimed at understanding the threat AQAM will pose in 2025.

“This effort entails gaining a keener sense of where these threats will be most prevalent in the coming years and what tools can be applied by state and nongovernmental actors to defeat AQAM,” the report says.