If it wasn’t a joke then it could be construed as a threat.
Threatening terrorism against the United States is a class C felony punishable by 10 years imprisonment under 18 U.S.C. § 2332b(c)(1)(g)
Quoted Tweet : Link to the Tweet
@Michael Malice
I never said it was a joke
I never said it was satire
#FreeRaif