You were heading down the right road, but you turned off at the wrong exit.
There was nothing wrong with ABC's transmitting the tape into the US.
But ABC was under obligation to turn the original tape over to the appropriate authorities, which would have been FBI or Homeland Security. The original might have contained forensic clues useful to FBI or HS.
Instead, ABC turned an edited copy over to the authorities, after removing 15 minutes that might have had a political impact. It was not ABC's province to make that decision or tamper with the evidence. This is where network employees crossed the line.
The fact that this was related to terrorism and not some petty crime puts it under PATRIOT.
I knew I veered off, but follow my logic.
Nothing forces something purchased (per another thread) by a presumed specially protected class (1st amendment can always get sticky, especially when dealing with a "legitimate" news organization) to be turned over to the US government, especially when the transaction has taken place in a foreign country. The transaction may have been between foreign nationals... Yes, I know there are portions of Patriot that address activities in foreign countries, but I think they are limited to banking or money laundering. The tape itself may have never made the trip from Pakistan to the US, though I do not know.
However, it's content was transmitted into the US, which is where an argument against the legality of intercepting the signal again is answered in Patriot. A legal intercept allows the US government to take jurisdiction, whereas an illegal intercept boots the thing out of court on the first round.
It's hard to argue for bad intent when it went to "a legitimate US news organization". Still, if the same feed was sent to a nefarious character, could it not be argued that the intent could be to "weaponize" it, by releasing it into the general population? We're wandering into equal protection territory here, so... I go back to making all of the content into contraband, an act of terror, which means no one can claim to have a right to legally claim it, to "own" it, to use it at will, even by a "legitimate media organization".
Failure to turn the entire thing over to the US government should be the only lawful action. I'm talking about any & all copies. Intent to disseminate, even a portion reaches into the most common example used to explain the limits on the 1st amendment, yelling fire in a crowded theater. Anything short of turning it over makes the news organization a partner in the crime, in this case an act of terrorism.