People have a constitutional right to be secure in their papers and effects and the court should be the one judging where these rights start and end, and not the FBI.
Exactly what is so important that a warrant cannot be obtained from a judge before tapping these lines? Where is the justification that this is necessary to secure our happiness and freedom?
If it is necessary to repeal parts of the constitution then we should have a frank, open and honest discussion about it. The more likely case is that Augustus has no clothes.
I wouldn't underestimate the extent to which the Commerce Clause could be applied.
The DoJ is well-aware of this, I'm sure, and is only too happy to throw its full weight around.
Officially, I think it's called the "brown nose" business model.