Really, we need to restore the understanding that if the law forbids something, it forbids paying someone else to do that thing. Murder is illegal, so it is also a crime to hire someone to commit murder. Government prying without a warrant is illegal, so buying the same information from someone else is just as illegal.
The NSA is not supposed to have any domestic operation at all. If they happen to capture a Citizens call at the foreign endpoint, that's one thing, but no call that stays in the U.S. should ever be seen by the NSA.
However, at this point, we would pretty much have to dismantle the NSA entirely and form it again to break their culture of lawlessness.