While the law hasn't changed, the prosecution policy has. USG had not charged the NYT, WP etc. with criminal publication of the Pentagon Papers, and of the many leaked classified data published before and since. A consistent change in the policy (prosecuting the NYT and its individual journalists and editors, and not just Assange) would have a huge impact on politics. An inconsistent change, successfully prosecuting but only charging the journalists that the current government finds inconvenient, would have a different but also huge impact.