[rayiner]

Who says the specific programs have been challenged in court? The argument is that they rest on principles that have been set forth in previous Supreme Court opinions.

Look at the EFF's handy image: https://www.eff.org/files/2015/03/19/backbone-2015-color.jpg.

Do you see the box labeled "filtering aimed at eliminating fully domestic transactions"? That's there because precedent says the 4th amendment does not protect things crossing the border. So the crux of the case is showing that the unconstitutional part happens in the first box--when the data is first copied.

In my opinion, none of it is protected once it's on the backbone. If hundreds of AT&T or Verizon engineers can access a data stream, it's not "private." But I also think the question should be litigated in court.

[spiralpolitik]

The question already has been litigated in court. To monitor a domestic phone conversion (which prior to digital exchanges the switchboard operator could listen into) requires a warrant to capture. Same principle here.

Just because something can be easily listened to doesn't mean the government doesn't need a warrant.