Friday's intelligence summary refers to "multiple streams of intelligence," including satellite detections, as backing up the claim that the Syrian regime killed more than 1,400 people, including at least 426 children, in a chemical-weapons attack on Aug. 21. But as part of that the summary refers in detail to "local social-media reports" that indicated the chemical attack began at 2:30 a.m., and "within the next four hours there were thousands of social-media reports on this attack from at least 12 different locations in the Damascus area," the report says. "Multiple accounts described chemical-filled rockets impacting opposition-controlled areas."

The report goes on to say that the U.S. intelligence community has "identified one hundred videos attributed to the attack, many of which show large numbers of bodies exhibiting physical signs consistent with, but not unique to, nerve-agent exposure." It added that "the Syrian opposition does not have the capability to fabricate all of the videos, physical symptoms verified by medical personnel and NGOs, and other information associated with this chemical attack."

Kerry, in his statement, said that just 90 minutes after the attack, "all hell broke loose on social media…. It was ordinary Syrian citizens who reported all of these horrors."

It remains to be seen whether the administration's case against Assad will stand up well in world opinion. But taken together with the remarkable way that, back in April, Boston police and federal authorities collected private video images and called upon the public to relay information about the Boston Marathon suspects on cell phones and social media, the Obama administration's intelligence case amounts to a new kind of evidence for the age of omnipresent data collection.

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