>Considering the fact that the US was completely caught off guard by the scope and effectiveness of ISIS I have to question the effectiveness of SIGINT programs like the NSA. I have to assume honestly that these programs outlandish budgets are not for tracking terrorists but to control the domestic populace.
I must disagree with this interpretation. I think that only the American public and (some) American media were caught off guard by ISIS. However, the warning signs about ISIS and speculation about the impact of instability in Syria go back a while, for example to early 2013. It would have been difficult to determine the exact sequence of events (in contrast, Lebanon has been more stable than some would have anticipated), but the expansion of ISIS operations is not so much of a surprise given 1) stated goal of ISIS to operate beyond Syria; 2) rising political tensions in Iraq encouraged by Maliki's disregard of opposition; 3) past actions of local Sunni militias and leaders, etc.
Maybe it looks like the US government was caught off guard, but I suspect that is not the case. I think US intelligence must have considered instability spreading out of Syria, and modeled a number of scenarios off of that. I think it is likely that the US gov. has not been so quick to respond because it realizes 1) there is little support in America for further involvement with Iraq; 2) there is limited support in the region for US involvement; 3) Maliki's government has leaned towards Iran, so the US may consider the ability to sustain American influence in Iraq limited.
In short I view this as a matter more of limited policy options than a matter of failed intelligence. I also think the more troublesome matter for intelligence is the Kurdish situation, since it is one thing to predict what ISIS will try to do and another to predict what will happen with the Kurdish autonomous region as a result.