Buckle your seatbelts, everyone....

[classicdrogn]

In the United States, the federal crime of witness tampering is defined by statute at 18 U.S.C. § 1512, which is entitled "tampering with a witness, victim, or an informant."

link

Well, whaddaya know, a felony. And what's a quick definition for "felony?" Why, I believe that would be a high crime. It certainly meets and surpasses the bar for a misdemeanour no matter how much leeway you give for a "high misdemeanour."