I understand Carter Page had in prior years been a paid FBI informant tasked to travel to Russian and spy on Russians. This parallels Misfud, who was a Western asset, not Russian. Both were later--without evidence--claimed to be Russian agents.
I would want to examine whatever evidence there might have been that Page supposedly "act[ed] as an agent for a foreign power" and whether it was opportunistically coincident with and/or led to (as in justifying as a predicate) the Trump campaign "counter-intelligence" investigation. Everything about Page and Misfud's previous work for the US intel community needs to be examined.
This parallels LHOswald's FBI informant status with regard to the JKF assassination. If that informant status had been gotten out, I don't believe anyone would now believe LHO was the "lone gunman" responsible.
I believe there's at least a three-way parallel among the ways the FBI was using 1) media (e.g., Isikoff), 2) Mifsud and 3) C. Page, each time, looking to get a return from things the FBI had actually (and clandestinely) instigated, later using the results as if they had simply come in over the transom and to justify greater intel-gathering operations, even a Special Counsel.
Page was an FBI/CIA asset. So obviously they lied when they got the warrant on him. My only question is, was he a witting participant. He has loudly proclaimed that he was innocent, that he was used, but I’m not convinced.
Still, he was Typhoid Mary, carrying a surveillance warrant over his head everywhere he went and passing it to everyone he met.