On the Sunday, June 9 edition of ABC News' This Week, the chairs of the Senate and House Intelligence Committees declared that recently disclosed National Security Agency (NSA) surveillance of phone-call "metadata" and Internet traffic involving U.S. citizens was largely responsible for two high-profile successes in the War on Terror.

The 2009 arrests of Najibullah Zazi and David Headley, said Sen. Dianne Feinstein (D-Calif.) and Rep. Mike Rogers (R-Mich.), wouldn't have happened without such programs.

Leaving aside important questions about whether such far-reaching surveillance is constitutional or prone to abuse, the claims by Feinstein and Rogers present the simplest, most-straightforward argument for the efficacy of the NSA's PRISM program and tracking of telecommunications involving Americans on American soil. However controversial and unsettling to many people, say Feinstein and Rogers, these programs are indispensable to keeping us all safe from harm.

Yet neither case cited by Feinstein and Rogers comes anywhere close to proving that the controversial programs had anything to do with thwarting violence in the United States or anywhere else. If published accounts, including court documents, are to be trusted (more on that later), Zazi and Headley aren't poster-children for the sort of surveillance that has apparently become the new normal. Far from it: Zazi was put away by traditional methods of tracking and watching a criminal and Headley was a former federal drug informant (!) whose terroristic leanings were revealed to the U.S. government years before he took any action.

As ABC News reported (watch video at that link too):

Both Feinstein and Rogers said that the phone and internet surveillance programs has been instrumental in stopping terrorist attacks, citing the 2009 terror plot by Najibullah Zazi, the Colorado resident who was arrested in Sept. 2009 after plotting to bomb the New York subway system. Feinstein said the program also helped to track the case of David Headley, a Pakistani-American who traveled to Mumbai to scope the Taj Mahal Hotel for an attack.

As Rogers put it,

"I can tell you, in the Zazi case in New York, it's exactly the program that was used," Rogers said, later adding, "I think the Zazi case is so important, because that's one you can specifically show that this was the key piece that allowed us to stop a bombing in the New York Subway system."

Actually, the Zazi case seems to be a vindication of what Buzzfeed's Ben Smith calls "old-fashioned police work." That is, the staking-out of specific individuals to whom officials had been directed by specific tips. British and American court documents, writes Smith, show that intelligence officers were monitoring a particular email address that had been linked to "an al Qaeda associate" by British and Pakistani agents.

An FBI agent, Eric Jurgenson, testified [at Zazi's 2011 trial], "I was notified, I should say. My office was in receipt of several e-mail messages, e-mail communications." Those emails—from Zazi to the same sana_pakhtana@yahoo.com—"led to the investigation," he testified.

British authorities learned of that Yahoo email address when they searched a computer of a terror suspect arrested in London in early 2009. They clued the Americans into the address, who then watched it.

A 2009 NPR account of Zazi's arrest further underscores that his capture came about less from stratospheric surveillance of all possible communications and more from intelligence gathering and information sharing among federal, state, and local police. In 2008, Zazi traveled to Pakistan and trained at a known al Qaeda camp, where he apparently learned the rudiments of bomb making. He was placed under surveillance upon his return to the United States.

"I think what's striking about the Zazi case is not so much that new tools were being used, but that old tools were being used in a comprehensive fashion," says Sam Rascoff, who used to work terrorism cases for the New York Police Department's intelligence unit. "And that they were being stitched together in a thoughtful, strategic way, so that one tool naturally gave way to another."

The Headley case similarly points away from the sort of ubiquitous dragging of communcations touted by Feinstein and Rogers and toward basic police work. Earlier this year, the Pakistani-American Headley—who went by his birth name Daood Gilani until 2006—was sentenced to 35 years in prison for his role in scouting locations for the 2008 Mumbai bombings that killed hundreds of people. He has also pleaded guilty to conspiring to attack the headquarters of the Danish newspaper Jyllands-Posten, which published cartoons critical of Islam.

Headley/Gilani was hardly an unknown character to federal law enforcement before his 2009 arrest. For years, he was a highly prized informant for the Drug Enforcement Administration (DEA), reported Pro Publica, and attended several Pakistani terrorist training camps between 2002 and 2005 while still apparently working for the DEA. In 2005, one of his wives (among his lesser crimes was being a bigamist), reported him to the Joint Terrorism Task Force after he allegedly beat her. The wife reportedly provided authorities with copies of tapes and other material showing he associated with Muslim extremists. Assuming standard protocols were followed, that incident would have triggered at least a preliminary report on Headley/Gilani, but it appears there was no follow up. Why not? From Pro Publica:

Investigators could have decided it simply wasn't worth pursuing, perhaps because [the terrorist group Lashkar-i-Taiba, with whom Headley/Gilani consorted] was seen primarily as a threat to India at that time. Others believe investigators learned Gilani was still an informant for the U.S. government so they deferred to the existing operation. But federal officials speaking on background say that to their knowledge Gilani was no longer an informant at that point. Another scenario: investigators may have opened a case and put him under surveillance. If he was an informant, his U.S. handlers could also have tracked his travels and intercepted his communications if they suspected wrongdoing and opened an investigation, officials said.

The New York Times reported in 2010 that Headley's Moroccan wife had two meetings in the U.S. embassy in Islamabad before the Mumbai attacks. The wife recounted the experience this way:

"I told them, he's either a terrorist, or he's working for you," she recalled saying to American officials at the United States Embassy in Islamabad. "Indirectly, they told me to get lost."

Another 2010 Pro Publica report credits British authorities with tipping off the FBI to Headley's plans to attack Jyllands-Posten. The Brits had been watching various Pakistani militants who called Headley "David the American" and contacted their U.S. counterparts, who eventually arrested Headley in the States.

Is the sort of NSA snooping that's in the news really instrumental to keeping us safe? "The instances where this has produced good—has disrupted plots, prevented terrorist attacks—is all classified," Feinstein said on This Week even as she and her House counterpart publicly discussed two such cases.

It's possible, of course, that the NSA and other intelligence sources scrubbed all possible references to top secret programs before newspaper articles were written and court testimony prepared. But given the relatively straightforward narratives behind the capture of Zazi and Headley—narratives in which "old tools" such as searching computers of suspects in custody and sharing information among agences play such clear roles—it seems highly unlikely.

At any rate, this much seems certain: In a world in which the Director of National Intelligence James Clapper has pretty transparently lied before a Senate committee and even The New York Times says that President Obama "has lost all credibility" on the surveillance issue, the public is right to be highly skeptical of any claims about the absolute necessity of increasing state power in the name of stopping terrorism.