Back when there was a US War Department, military budgets were cut substantially in times of peace. Civilian oversight also kept fairly tight reigns on military endeavors to ensure revenue allocations were reasonably well spent. At the end of WWII for example ceilings were imposed on military expenditures and the term war had become so unpopular that the department was renamed within a couple of years to Department of Defense. Nonetheless by 1950 DoD was embroiled in the undeclared Korean War, incidentally fueling a burst of inflation and nullifying military monetary ceilings. In 1951 General MacArthur solicited public support for expanding that war into China. President Truman knew MacArthur to be without complete information and consequently ignorant of the probable ramifications of that action. Without wide counsel Truman quickly recalled "Mr. Prima Donna, Brass-Hat, Five-Star MacArthur" from Korea likely avoiding WWIII as he indicates in his private papers.
The point to be made here is that once upon a time US civilian leadership was relatively strong and able to effectively oversee military matters. Nowadays militarized government departments habitually dictate policy to US presidents. As specific example the current POTUS publicly has expressed willingness to govern in accordance with whatever the militarized "intelligence community feels is required to keep people safe". Stronger leadership attuned to constitutional values might analyze and balance traditional American principles, mass surveillance ineffectiveness, and abuse of surveillance data against what NSA, a DoD component, claims is necessary.
There is little doubt that JFK might have fired both James Clapper and Keith Alexander months ago for characteristically military arrogance. Clapper psychopathically repetitively lies to Congress without remorse and Alexander unapologetically oversteps authority at every opportunity. The current administration's Svengali undoubtedly is DoD itself of which NSA is only a part. Of course any curtailment of surveillance would mean withstanding shallow accusations following the next inevitable terrorist attack on US soil. JFK was a master at making downsides palatable in favor of preserving principle: "Even today, there is little value in insuring the survival of our nation if our traditions do not survive with it".
Right now POTUS could be manning the bully pulpit to hold failed congressional overseers accountable. Senator Diane Feinstein and Representative Mike Rogers head up the Intelligence Committees for the Senate and House respectively. Having been tasked with oversight of intelligence operations these two arguably hold the greatest culpability for the entire Snowden affair. If their committees were properly overseeing NSA, that agency would unequivocally operate within domestic, international, and constitutional law. Unfortunately specious oversight allowed NSA to get so far out of touch with traditional American values and reality that a brave young man decided to do something about it at great personal risk.
Congressional overseers are sworn to "support and defend the Constitution of the United States against all enemies, foreign and domestic" nevertheless contemporary focus supports and defends intelligence communities irrespective of methodologies used. Rather than overseeing they appear to be conspiring and consequently might arguably be classified eventually as burgeoning domestic enemies.
What is truly frightening about all this is that Americans don't seem to notice at all the de facto constraints of civilian oversight. That's an enormous slice of apple pie gone perhaps forever. Back in February, 2012, it was written that: "American ideals are well beyond salvation and ... government policies and civilian responses ultimately are apt to mimic Egyptian drama emanating from Tahrir Square with citizens espousing civilian oversight of the military." No matter what is written or by whom or how often, too many Americans will always foolishly believe government's character and intentions to be social rather than antisocial. It's human nature. Everyone says "government is a necessary evil" but no one wants to believe his own government capable of evil. Nevertheless effective oversight is crucial.