Obama ran on the promise to end domestic spying by the NSA, and as president he would have had the authority to do it at any time, but once he got into office he expanded the domestic spying program. The most simple explanation is that he lied through his teeth and that he had no intention of stopping it.

It's also possible that once he got elected he was convinced that it was so worthwhile that it was worth violating his campaign promises, but what worries me most is the possibility that Obama honestly believed, and still believes, that it was a unacceptable violation of our constitutional rights and that he only had to be shown a sample of the data collected on him and his family to get him to fall in line and approve whatever the NSA wanted.

"If you give me six lines written by the hand of the most honest of men, I will find something in them which will hang him." The NSA has so much data on us that they could blackmail anyone, and could likely plant incriminating data as well. That power exists for them to use at any time. If they're willing to use it in order to keep that power over anyone they see as an enemy then it's possible that no president or politician will ever be able to do anything to stop America's domestic spying program.