Since news reports in early August revealed that the United States intercepted messages between Ayman al-Zawahri, who succeeded Osama bin Laden as the head of Al Qaeda, and Nasser al-Wuhayshi, the head of the Yemen-based Al Qaeda in the Arabian Peninsula, discussing an imminent terrorist attack, analysts have detected a sharp drop in the terrorists’ use of a major communications channel that the authorities were monitoring. Since August, senior American officials have been scrambling to find new ways to surveil the electronic messages and conversations of Al Qaeda’s leaders and operatives...
The drop in message traffic after the communication intercepts contrasts with what analysts describe as a far more muted impact on counterterrorism efforts from the disclosures by Mr. Snowden of the broad capabilities of N.S.A. surveillance programs. Instead of terrorists moving away from electronic communications after those disclosures, analysts have detected terrorists mainly talking about the information that Mr. Snowden has disclosed.
Senior American officials say that Mr. Snowden’s disclosures have had a broader impact on national security in general, including counterterrorism efforts. This includes fears that Russia and China now have more technical details about the N.S.A. surveillance programs. Diplomatic ties have also been damaged, and among the results was the decision by Brazil’s president, Dilma Rousseff, to postpone a state visit to the United States in protest over revelations that the agency spied on her, her top aides and Brazil’s largest company, the oil giant Petrobras.
