"In this instance the gain from that information is likely to be minimal," Pillar said. "Sound analysis on international economic issues of concern to U.S. policymakers is apt to draw more from other sources of information, both secret and public, and from tapping relevant expertise both outside and inside government, than from eavesdropping on conversations at the IMF," he added.
It is no secret that U.S. spy agencies historically have collected and analyzed information related to economic affairs - in public briefings to Congress, top intelligence officials have discussed assessments of economic issues.
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But a former senior U.S. intelligence official said that the Obama Administration had put greater emphasis and resources than predecessors into collecting and assessing economic information.
In February 2009, shortly after Obama entered the White House, the Central Intelligence Agency began producing a new "Economic Intelligence Brief" for him to review along with the regular President's Daily Brief on international security and threats.
Leon Panetta, Obama's first CIA director, said at the time the change was aimed at understanding the implications of the global economic crisis, and that the agency was considering hiring more economic analysts.
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The former U.S. intelligence official noted that insider detail on economic policy developments - for example, financial crises affecting the economies of European countries such as Greece, Italy and Spain, and the stability of the Euro - is the type of critical information U.S. policymakers welcome.
The desire by U.S. policymakers for such information could help explain why NSA collected information on foreign leaders such as Merkel. Her cellphone number was listed in a NSA targeting document, which German media outlets apparently obtained from Snowden's cache. U.S. officials have now indicated that much NSA eavesdropping on Merkel and other allied leaders is likely to be curtailed if not halted.