In Gorin v. United States (1941), the Supreme Court heard a challenge to a conviction of a Navy intelligence official who sold classified material to the Soviet Union on Japanese intelligence operations in the United States. In that case, the defendant was charged with selling information “relating to the national defense” to a foreign power. The defendant argued on appeal that the phrase “relating to the national defense” was unconstitutionally vague, so much so that the defendant was deprived of the ability to predetermine whether his actions were a crime.
Justice Stanley Reed wrote the majority opinion and disagreed that the law was unconstitutionally vague, but only
on the very narrow grounds that the law required “intent or reason to believe that the information to be obtained is to be used to the injury of the United States.” Only because the court read the law to require scienter, or bad faith, before a conviction could be sustained was the law constitutional. Otherwise, it would be too difficult for a defendant to know when exactly material related to the national defense.
The court made clear that if the law criminalized the simple mishandling of classified information, it would not survive constitutional scrutiny, writing:
The sections are not simple prohibitions against obtaining or delivering to foreign powers information… relating to national defense. If this were the language, it would need to be tested by the inquiry as to whether it had double meaning or forced anyone, at his peril, to speculate as to whether certain actions violated the statute.
In other words,
the defendant had to intend for his conduct to benefit a foreign power for his actions to violate 793(f).
Without the requirement of intent, the phrase “relating to the national defense” would be unconstitutionally vague. This reading of the statute has guided federal prosecutors ever since, which is why Comey based his decision not to file charges on Clinton’s lack of intent. This is also why no one has ever been convicted of violating 793(f) on a gross negligence theory.
https://warontherocks.com/2016/07/why-intent-not-gross-negligence-is-the-standard-in-clinton-case/