Why Paris Could Happen Here

From Mitchell Silber, at WSJ, "The elements of an attack are available, including the weapons, manpower and a ‘permissive environment’":

In the afternoon of Nov. 13, when news of the horrific Paris attacks began to reach the U.S. and the fear and chaos there began to sink in, many Americans asked one important question: Could a similar attack by jihadists linked to Islamic State occur in a major American city? The answer is yes.

To understand why, it is vital to deconstruct the Paris attack and the factors that enabled it and then see if they can be mapped onto an American urban environment. During my tenure as director of intelligence analysis at the New York Police Department, this is what we did after any major attack around the world to stay ahead of ever-evolving terrorist threats.

While more operational details of the Paris attack will be uncovered, four necessary ingredients have already emerged: First, European citizens willing to kill themselves and their countrymen. Second, material for the attack, including assault weapons and hydrogen peroxide for suicide bombs. Third, the technical and paramilitary skills to make improvised explosive devices and operate assault weapons. And fourth, a “permissive environment” in which the national and local security and intelligence agencies were not able to detect the plot in advance.

Thankfully, the United States has—in absolute numbers and per capita—significantly fewer members of its Muslim population who are alienated from American society, inspired by Islamic State’s toxic ideology and radicalized to violence. But they do exist. As FBI Director James Comey recently noted, the bureau has more than 900 active ISIS investigations in 50 states. Those are just the domestic ISIS supporters that the FBI knows about. In May two ISIS-inspired American citizens, Elton Simpson and Nadir Soofi, stormed an event featuring Muhammad cartoons in Garland, Texas, wearing body armor and carrying assault weapons. If it were not for the good work of law enforcement, who shot and killed the men, scores may have been murdered.

What about material? Semiautomatic weapons with high-capacity magazines are fairly easy to acquire, legally or illegally. Hydrogen peroxide, the active ingredient for deadly triacetone triperoxide (TATP) explosives, is sold throughout the U.S. and requires only patience and small purchases at different locations to acquire enough for multiple explosive devices. The technical know-how to make operational explosive devices can be obtained through online tutorials or more directly (and thoroughly) by traveling overseas to training camps.

Mr. Comey told Congress this summer that upward of 200 Americans have traveled or attempted to travel to Syria to participate in the conflict. According to Director of National Intelligence James Clapper, about 40 of those Americans have returned from the jihadist battlefields of Syria since that civil war began.

In May 2014, a U.S. citizen from Florida, 22-year-old Moner Abu-Salha, carried out a suicide-bomb attack for the al Qaeda-affiliated Jabhat al-Nusra in Syria. After training in Syria he had traveled undetected to and from the U.S. There are likely more American citizens like Moner Abu-Salha.

As for the permissive environment: Some analysts argue that French and Belgian intelligence services and police are overwhelmed by the sheer number of potential terrorists, but that U.S. agencies aren’t as stressed and won’t miss anyone. That is dangerous and inaccurate. The 2013 Boston Marathon attack by the Tsarnaev brothers was not that long ago. In that case the FBI received warnings from Russia, conducted its own investigation of Tamerlan Tsarnaev and then—despite his travel to a potential zone of conflict in the Caucasus and a pro-jihadist social-media profile—closed its investigation.

Police and intelligence agencies have an enormously difficult job because radicalization pathways to violence are not always straightforward...

Still more.