That is where he is wrong.
They literally could.
The witch is dead?
Verifying the FISA was never the goal.
How else do you keep the investigation going on forever?
It's like a limited hangout - a few simple true items to make it plausible, then fill the rest with complete bullshit that can never be proven (or unproven).
It's only a problem from a FISA legality standpoint.
But they never thought she would lose.