Initially, based on the news reports that Americans were targeted for surveillance under this program.
Then, based on the fact that the President confirmed the reports.
Do you really have no idea what the controversy is about?
At some point, the MSM substituted the term "Domestic Spying" in place of "exclusive surveillance on international communications".
Intercepting international communications outside US borders is one thing. Tapping someone's phone and listening in to all domestic calls is something else. So far, there has been absolutely no indication that the latter has occurred. If you can find me an article which affirms this, then by all means post it. Until then, I would be careful in repeating the lie that individual Americans were under surveillance.
As my understanding, the targets of the surveillance have been international al Qaeda operatives. To suggest that surveillance of these operatives cease once they have contacted someone inside our borders is ludicrous.