I used to live in a (now ex-)communist country, where state authorities blatantly breaching citizens' privacy and spying on their every activity was pretty much usual.
You're in great error thinking this has something -- anything -- to do with a president in particular, or with a few people at the top of the decision-making chain. It doesn't. My own country changed two dictators (and a handful of "democratic" regimes afterwards) without this matter being solved.
It's a combination of two things:
* A large block that supports such decisions and even actively pushes for them. The elected President will only be there to implement them for two terms at most, but the people supporting them have no cap on their term. Since two presidents from two different parties (it doesn't help that they're basically the only two parties you have...) did similar shit, it's only safe to assume that either both parties have such groups, or that the groups who are supporting them aren't affiliated to any party in particular.
* Woeful lack of alternatives from your voters and, quite possibly, misinformed voting (although the second is something I can only intuitively state, as I don't live in the US). The people who deal in power are greedy; if they had any reason to believe this kind of stuff would have their asses bust out of office, they'd stop doing it. However, my own experience tells me what they feel is that this kind of crap actually ensures their continuous tenure in their offices.
Also, while we would all wish everyone realized how dangerous this is, the sad truth is most people don't care, or don't realize the atrocity of it. We are a minority; a handful of well-educated people who can think for themselves and who can fully grasp the intrusiveness of such surveillance. Most people simply don't realize enough to care that "the State" (whatever the hell that is) knows who they were calling and when -- after all, who in the world has time to sift through all those pages of phone calls, eh?