They're supposed to be "one of the centerpieces of our counterterrorism strategy," according to Janet Napolitano, the Secretary of the Department of Homeland Security. In practice, not so much.

The Senate's bipartisan Permanent Subcommittee on Investigations found no evidence that DHS' 70-plus fusion centers – places where state, local and federal law enforcement analyze and share information – uncovered a single terrorist threat between April 1, 2009 and April 30, 2010. Terrorism is thankfully rare within the United States. But during that time, the FBI discovered would-be New York subway attacker Najibullah Zazi; U.S. Army Major Nidal Malik Hasan killed 13 people at Fort Hood; Umar Farouk Abdulmutallab tried to blow up a Detroit-bound airplane; and, in early May 2010, Faisal Shahzad attempted to detonate an SUV in Times Square. DHS has praised the fusion centers' work in helping on the Zazi and Shahzad cases. The Senate found fusion centers played little, if any, role in either case.

"Nor," the Senate panel writes in its just-released report, analyzing more than 80,000 fusion center documents, "could [the inquiry] identify a contribution such fusion center reporting made to disrupt an active terrorist plot." Unnamed DHS officials told the panel the fusion centers produce "predominantly useless information" and "a bunch of crap." An internal 2010 assessment, which DHS did not share with Congress, found that a third of all fusion centers don't have defined procedures for sharing intelligence – "one of the prime reasons for their existence." At least four fusion centers identified by DHS "do not exist," the Senate found.

As civil libertarian groups have long warned (.pdf), those that do are hives of incompetence, bureaucracy, mission creep and possible civil-liberties abuses. Despite instituting privacy protections in 2009, the Senate report discloses, "DHS continued to store troubling intelligence reports from fusion centers on U.S. persons, possibly in violation of the Privacy Act." A third of reviewed fusion center intelligence reports either "lacked any useful information" on terrorism or potentially violated civil liberties. Other reports sat for months, until their information was "obsolete" by the time DHS published it. Instead of focusing on terrorism, "most information" from the centers was about ordinary crime, such as "drug, cash or human smuggling."

What's more, fusion centers are only supposed to analyze and spread information, not collect it. But along the way, they scooped up items like a leaflet for the Mongols motorcycle club in California telling bikers to be "courteous" to police. Oh, and a notation that a U.S. citizen was speaking at a mosque – without any derogatory information about either the citizen or the mosque.

Five centers the Senate studied spent their federal terrorism grant money on "hidden 'shirt button' cameras," cellphone tracking systems and other surveillance tools. They also spent their cash on things like "dozens of flat-screen TVs" and SUVs – sometimes claiming that Chevrolet Tahoes were intended to help "respond to chemical, biological, radiological, nuclear, and explosive (CBRNE) incidents." Others used fusion-center money to purchase equipment for medical examiners.The Department of Homeland Security compiled and disseminated the following information as part of a post-9/11 partnership with state and local law enforcement to prevent terrorism: DHS doesn't appear to care how it spends its cash. The Senate inquiry determined that DHS was "unable to produce a complete and accurate tally of the expense of its support for fusion centers." Its estimates range between $289 million and $1.4 billion. In other words, DHS doesn't even know how much money it's spent on what it calls a centerpiece of its counterterrorism strategy.

And the fusion centers, in the Senate's telling, have a hard time balancing civil liberties and rapid analysis. After DHS analyst Daryl Johnson's 2009 report about right-wing extremism caused a popular backlash, Deputy Secretary Jane Holl Lute ordered that fusion-center intelligence products had to go through a bureaucratic, multi-agency review for potential civil-liberties violations. For the past three years, the review has "radically slowed down the reporting process" – which might be problematic, if the fusion centers were actually uncovering terrorist plots.

But they're not. The Senate reviewed 610 draft reports from fusion centers between April 2009 and April 2010. The vast majority of them came from three states: Texas, California and Arizona. Nearly a third of them, 188, were "cancelled," either because they lacked "useful information" or "for running afoul of departmental guidelines meant to guard against civil liberties or Privacy Act protections." Only 94 were in any way related to terrorism.

"Of those 94 reports," the Senate found, "most were published months after they were received; more than a quarter appeared to duplicate a faster intelligence-sharing process administered by the FBI; and some were based on information drawn from publicly available websites or dated public reports." One such report, in November 2009, reported that al-Qaida propagandist Anwar Awlaki praised the Fort Hood attacks – four days after the Los Angeles Times reported that. "Surprisingly," the Senate found, "a subsequent performance review for the [report's] author cited this report as a signature accomplishment."

Some fusion centers simply don't care about terrorism. A Senate survey of 62 fusion centers in 2010 found that more than one-third of them, 25, didn't even "mention terrorism in their mission statements." Instead, they take federal anti-terrorism money and use it to supplement local law-enforcement priorities like fighting drugs, under the pretext that terrorists "would commit precursor crimes before an attack."

Others get in the way of law-enforcement efforts. One of these cases, involving an alleged Russian "cyberattack" in Illinois, is covered by my Wired colleague Kim Zetter at Threat Level. (Quick preview: DHS doesn't exactly come out looking like a coven of geniuses.) Another involved the Arizona fusion center, which mistakenly reported in January 2011 that the would-be assassin of Rep. Gabrielle Giffords was connected to an "anti-Semitic, anti-government group" called American Renaissance. The "group" in question is actually a newsletter, and the fusion center's director had to publicly state the analysis shouldn't have been released. A third, released by the Missouri fusion center, tied libertarians and supporters of Ron Paul to "the Modern Militia Movement," strongly suggesting they were violent anti-government extremists.

The Senate report stops far short of recommending that the fusion centers be abolished. It argues instead for stricter oversight and sharper clarifications of the fusion centers' counterterrorism mission. But it's worth considering what the director of the northern California fusion center told a Senate panel in 2011.

The director, Ronald Brooks, mentioned that there isn't any transnational terrorism in Oakland. But Oakland did have 740 recent shootings, and so he defended spending federal terrorism grants solving those crimes. "That’s terror right there in our own community," Brooks said. "And that kind of terror is one that’s experienced in big cities and small towns across the country."

Brooks probably meant to be a good cop. But even good cops can go bad when they're handed lots of cash to chase rare threats to national security.