The Supreme Court ruled Tuesday to make it more difficult to convict a person of making a violent threat. The case could make it harder for prosecutors to convict certain people who threaten elected officials.

The high court ruled in a case that involves a man who was sentenced to more than four years in prison in Colorado for sending threatening Facebook messages. The man’s lawyers had argued that he suffers from mental illness and never intended his messages to be threatening.

Officials said that violent threats against public officials have increased in recent years. The internet and social media generally have expanded the number and kind of threats including online harassment, intimidation and stalking.

The question for the court was whether prosecutors must show that a person being prosecuted for making a threat knew their behavior was threatening or whether prosecutors just have to prove that a reasonable person would see it as threatening.

Justice Elena Kagan wrote for a majority of the court that prosecutors have to show that “the defendant had some subjective understanding of the threatening nature of his statements.”

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The Associated Press contributed to this article.