Nevertheless, there is a rear-guard action in Congress to make it more difficult to gather, use and protect intelligence—the only weapon that can prevent an attack rather than simply punish one after the fact. The USA Patriot Act, enacted in the aftermath of 9/11, is a case in point.

This law has a series of provisions that will expire unless Congress renews them. Up for renewal this year is a provision that permits investigators to maintain surveillance of sophisticated terrorists who change cell phones frequently to evade detection. This kind of surveillance is known as “roving wiretaps.” Also up for renewal are authorizations to seek court orders to examine business records in national security investigations, and to conduct national security investigations even when investigators cannot prove a particular target is connected to a particular terrorist organization or foreign power—known as “lone wolf” authority…

Those who indulge paranoid fantasies of government investigators snooping on the books they take out of the library, and who would roll back current authorities in the name of protecting civil liberties, should consider what legislation will be proposed and passed if the next Najibullah Zazi is not detected.