Final answer:
The highest security classification for materials transmitted via US Postal Service first class mail is Confidential. Top Secret materials are not suitable for this method due to the high level of sensitivity and security required.
Step-by-step explanation:
The highest security classification authorized to be transmitted via US Postal Service first class mail is Confidential. The security classifications in ascending order of sensitivity are: Restricted, Confidential, Secret, and Top Secret. The US Postal Service regulations state that first class mail is intended for documents where the loss, payload, or unlawful disclosure could be expected to cause damage to the national security. Therefore, the most sensitive material, such as Top Secret, would not be suitable for this mode of shipping. In contrast, Restricted material generally denotes information that is not highly sensitive but is still controlled in access.
The highest security classification for materials transmitted via US Postal Service first class mail is Confidential. Top Secret materials are not suitable for this method due to the high level of sensitivity and security required. Regarding the right of the press to print classified material, the Supreme Court held that this right is partial, and the press may print classified material only if it does not compromise troops or covert operatives, indicating a balance between the right to freedom of the press and the need to protect national security.