News that the National Security Agency has overstepped its legal authority thousands of times in recent years is ratcheting up pressure on President Obama to accept reforms to the surveillance programs.

Last Friday, Obama tried to quell the growing uproar over NSA spying by laying out a series of steps to increase transparency and toughen privacy protections. He insisted the programs are critical to national security, but he acknowledged that certain changes might be necessary to restore the public’s confidence.

But the latest revelations about widespread privacy violations mean the NSA controversy is unlikely to die down anytime soon.

The news also raises the stakes for the White House’s decision about whom to appoint to an NSA review board. Obama promised the review group would be made up of independent experts. If he chooses only longtime intelligence officials, he is likely to spark further outrage from privacy advocates.