[takeda]

You know the answer to this, but that's not the point. The old system did not prevent crooked agent to have access as well.

The problem here is much bigger, because they assume that no one in the world (including foreign governments) would be able to figure out how to exploit backdoor(s).

Imagine a foreign government eventually would discover it. Such knowledge would be extremely powerful weapon in cyber warfare. What McCain is suggesting is extremely dumb, even if he's not concerned about our privacy.