Is kava illegal in USA?

Could you please clarify for me the legality of kava in the United States? I've heard conflicting information about whether it's permitted or prohibited. Could you provide some insight into this matter? Is there a specific law or regulation that governs the use or sale of kava in the US? If it's illegal, what are the consequences for those who consume or distribute it? Additionally, are there any exceptions or special circumstances where kava might be allowed? I'm interested in understanding the legal framework surrounding this topic. Thank you for your assistance.