If so, why?

Here are 5 terrifying scenarios:

1) China manages to get the NSA data.

2) Russia manages to get the NSA data. (It isn't like they never succeeded in placing spies in our government before.)

3) Pakistan manages to get the NSA data. (They pulled off stealing the West's nuclear secrets.)

4) Iran manages to get the NSA data.

5) Saudi Arabia manages to get the NSA data.

Of course, it could be a non-state actor that gets ahold of the data too. Perhaps a successor to Al Qaeda.

What if one of these entities breached the database's security without our even knowing?

Even assuming the U.S. government never abuses this data -- and there is no reason to assume that! -- why isn't the burgeoning trove more dangerous to keep than it is to foreswear? Can anyone persuasively argue that it's virtually impossible for a foreign power to ever gain access to it? Can anyone persuasively argue that if they did gain access to years of private phone records, email, private files, and other data on millions of Americans, it wouldn't be hugely damaging?

Think of all the things the ruling class never thought we'd find out about the War on Terrorism that we now know. Why isn't the creation of this data trove just the latest shortsighted action by national security officials who constantly overestimate how much of what they do can be kept secret? Suggested rule of thumb: Don't create a dataset of choice that you can't bear to have breached.