Could Snowden actually have Obama by the balls?
Yes!
If Snowden plays his hand smartly he will have them by the short hairs.
The NSA’s reputation is in the gutter while Snowden’s is rising.
At a certain point the NSA will be totally unable to disprove anything Snowden presents as data supposedly gleaned from NSA data stores. As long as the data is plausible and delivered smartly any attempt to discount it will just lend more credence to it. The NSA is not in a enviable position at all in this mess of their own making.