Two men have been charged in New York City with plans to bomb a subway station in Manhattan — a block away from the site of the Republican National Convention. Police say the men — Pakistani citizen Shahawar M. Siraj and James Elshafay, a Pakistan-born U.S. citizen — planned to use backpack bombs in the attack and had gone so far as to draw sketches of the Herald Square station where they allegedly planned to pull it off. However, New York Police Commissioner Ray Kelly made it clear that officials do not believe the suspects, who had been under surveillance before their arrest, actually are al Qaeda members — saying instead that "their motive was generally hatred for America." This statement in itself opens up several lines of discussion, including the structure of al Qaeda and the possibility that grassroots sympathizers might attempt to launch strikes on their own. A formal affiliation with al Qaeda certainly is not necessary to pull off an effective operation — something that points to increased risks both for the targeted and, in some ways, for the would-be operatives. One of al Qaeda's strengths is its lack of a formal structure: It is a loose organization of regional cells, acting semi-autonomously — in line with the group's strategic goals. Amongst ourselves, STRATFOR long has referred to an "al Qaeda prime" — the top leadership, which might approve or decline to support plans submitted by regional cells — and subgroups or affiliated organizations (for instance, Jemaah Islamiyah). This type of interaction, or rather lack thereof, was evident in the March 11 attacks in Madrid, where the train bombers are believed to have carried out their attack autonomously. Considering the relatively small price tag associated with many acts of terrorism, this structure makes it all the more possible for groups or individuals to carry out acts on their own, without financial support from al Qaeda prime. In assessing the likelihood of a major attack supported or planned by al Qaeda prime, we have returned many times to the leadership's core strategic goals — which include capturing the attention of Muslims around the world. That means that targets in such an attack are likely to be highly symbolic and well-recognized in the Islamic world, and that particular thought would be given to perceptions of the attack on the streets of Karachi and Riyadh — as much as (or more so than) than on the streets of Chicago and Dallas. Targeting a subway — as in the Madrid case — certainly carries the potential for catastrophic casualty counts, but would lack the symbolic value or direct financial impacts that al Qaeda also seeks. In the United States, an attack against transportation infrastructure has appeared to be a rather less likely scenario than many others, when viewed through the lens of al Qaeda's strategic vision. That said, the possibility that a small segment of American Muslim youth who are susceptible to militant ideology might be motivated to act on their own requires a separate — and much broader — assessment of which targets are most vulnerable. Threats to transportation infrastructure in major cities is not groundbreaking news. In the wake of the March 11 bombings, intelligence and law enforcement agencies fretted over these vulnerabilities — for subways in particular. Subway systems are simply too large and too heavily used and operate on schedules too tight to allow authorities to secure them in the same way that U.S. airports are. Placing backpack bombs on trains or near trash cans — either to gauge reactions and response times or in order to carry off a highly effective attack — would be completely within the reach of lone-wolf operators or even relatively untrained youths, with some guidance. Jihadist literature is now abundantly available through the Internet, with publications like Maaskar al-Battaar issuing regular calls to jihad and offering tactical guidance on weapons and methods. Though there is no evidence that the two suspects in the New York case, Siraj and Elshafay, took their cues from such publications (or even would have understood it in the Arabic-language original), translations are available. Though the possibility of lone-wolf actions calls into question any standing assumptions about the relative likelihood of threats against specific targets, one caveat is important: By definition, any "cells" of grassroots sympathizers are likely to be operating with far less security than their highly trained al Qaeda cousins. In the case of the New York suspects, Elshafay and Siraj were handed up by a friend and confidant who had been "turned" by the NYPD's intelligence unit, and who aided police in conducting surveillance and taping their conversations. Moreover, the pre-emptive arrests prior to the Republican National Convention show that police weren't willing to take any chances.