Carter Page was used for no other reason than they needed a FISA warrant to spy on the Trump campaign, hence he was never charged with anything. I've never really trusted the fella, and I don't know if he was playing along or if he really was oblivious, but what we do know is he had a long career with the CIA. I guess Durham if the person with the right credentials to dig into this, and maybe we will never know the answer due to state secrets.