Should the US Government spy on citizens?

Millions of Americans were shocked when Edward Snowden, an NSA employee, leaked thousands of documents that confirmed that the US Government was spying people all around the world.
It disclosed in something alarming: for years, the US Government had been spying people’s phone calls and e-mails. What was most impressive of all was that it was not only spying on people like you and me, but also world leaders such as Germany’s chancellor, Angela Merkel, and Brazilian President Dilma Rousseff.
Edward Snowden said free people shouldn’t live under surveillance. That was why he leaked the documents –he wanted people to know their government was violating their privacy. So then a huge discussion started: was the US Government violating the Constitution?
There seem to be lots of different approaches to something that should be very clear. For example, and according to the magazine The Atlantic, “a federal trial judge in Washington boldly declared the NSA's bulk metadata collection program to be ‘ikely unconstitutional,’ as applied to individual citizens whose phone records were collected and stored” (1). However, that same article in The Atlantic states that “a federal trial judge in New York boldly declared that very same surveillance program is constitutional as applied to the ACLU, the phone records of which also were collected and stored” (2).
Another problem analysts find is that the NSA spying would undermine the separation of powers. According to an article from USA Today, “as the Framers conceived it, our system of government is divided into three branches -- the executive, legislative and judicial -- each of which is