Death Star
Enforcing the UCI rules of forbidding racing in non-uci events wasn't working and USAC's continuing embarrassment that Colorado's road racing was nearly all ACA.
ACA's choice was to join USAC or end up bankrupt. USAC was threatening to start it's own association and then kill the ACA. It's the equivalent of organized crime shakedown, "Nice race federation you have there... It would be a shame if something bad happened to it. I sell protection insurance..."
More bad news for U.S. bike racing.