> the authorities truly believe that these leaks are aiding terrorists to evade their surveillance
Even if that were true, leaking documents that aid terrorists is not same as being a terrorist. If it were, they would have arrested Miranda and charged him with being a terrorist. They did not, because they knew full well that he's not a terrorist. Their opinion that he's carrying stolen property or that he's like a drug mule also does not make him a terrorist. Thus it is illegal for the government to use powers that are it's only allowed to use in determining if someone is a terrorist.
Even if that were true, leaking documents that aid terrorists is not same as being a terrorist. If it were, they would have arrested Miranda and charged him with being a terrorist. They did not, because they knew full well that he's not a terrorist. Their opinion that he's carrying stolen property or that he's like a drug mule also does not make him a terrorist. Thus it is illegal for the government to use powers that are it's only allowed to use in determining if someone is a terrorist.