Edward Snowden, seen during a video interview with The Guardian. Glenn Greenwald/Laura Poitras /EPA/LANDOV hide caption

itoggle caption Glenn Greenwald/Laura Poitras /EPA/LANDOV

The National Security Agency building at Fort Meade, Md. Charles Dharapak/AP hide caption

itoggle caption Charles Dharapak/AP

Cell towers are constantly tracking the location of mobile phones. And that data, federal courts have ruled, is not constitutionally protected. Steve Greer/iStockphoto.com hide caption

itoggle caption Steve Greer/iStockphoto.com

President Obama and German Chancellor Angela Merkel at a news conference in Berlin in June. A German newspaper reported Sunday that Obama had known since 2010 that his intelligence service was eavesdropping on Merkel. The story came a day after reports alleged Obama told Merkel he was not aware she was being spied on. Kevin Lamarque/Reuters /Landov hide caption

itoggle caption Kevin Lamarque/Reuters /Landov

The U.S. ambassador to Spain, James Costos, leaves the Spanish Foreign Ministry after being summoned to a meeting in Madrid on Monday. He was called in following reports that the NSA was tracking millions of phone calls in Spain. Juan Medina/Reuters /Landov hide caption

itoggle caption Juan Medina/Reuters /Landov

In this photo released by China's Xinhua News Agency, ousted Chinese politician Bo Xilai stands before the Shandong Provincial Higher People's Court. The court upheld Bo's conviction and life sentence for corruption and abuse of power. Xie Huanchi/AP hide caption

itoggle caption Xie Huanchi/AP

Massive government surveillance of Americans' phone and Internet activity is drawing protests from civil liberties groups, but major legal obstacles stand in the way of any full-blown court hearing on the practice. Among them: government claims that national security secrets will be revealed if the cases are allowed to proceed. Patrick Semansky/AP hide caption

itoggle caption Patrick Semansky/AP

U.S. Ambassador to France Charles Rivkin (in red tie) leaves the Foreign Ministry in Paris after being summoned Monday following reports that the National Security Agency spied on French citizens. Thibault Camus/AP hide caption

itoggle caption Thibault Camus/AP