What sdog said matches my recall on this.

Have an AMA membership and be race licensed by someone on the AMA list of approved licensing bodies.

American Federation of Motorcyclists (AFM)
Arroyo Seco Motorcyclist Association (ASMA)
American Sportbike Racing Association (ASRA)
Championship Cup Series (CCS)
Central Motorcycle Roadracing Association (CMRA)
Central Roadracing Association Inc. (CRA)
Loudon Road Racing Series (LRRS)
Motorcycle Riders Association (MRA)
Oregon Motorcycle Road Racing Association (OMRRA)
Team Pro-Motion GP Moto Elite
Sandia Motorcycle Roadracing Inc. (SMRI)
Utah Sportbike Association (USBA)
Chuckwalla Valley Motorcycle Association (CVMA)
WERA Motorcycle Roadracing (WERA)
Washington Motorcycle Road Racing Association (WMRRA)
MotoWest Grand Prix (MWGP)
It seems as if the AMA may be providing a warning for being licensed next year, about "AMA Affiliation", but doesn't matter for now.