It would really depend on what form the initial wave of repression takes. If, as is likely, it's something akin the the Parents Music Resource Center(Tipper Gore et al) and the congressional hearings to get labels on rock music, it would probably just result in a few televised showdowns between the gaming industry and some grandstanding politicians, where everyone plays to their respective audience, and the forces of censorship likely throw in the towel after garnering whatever degree of electoral support they can from their posturing.
On the other hand, if we're talking federal legislation to outlaw DND, enforced by police agencies, then as has already been pointed out, we're probably already into a major dystopian scenario a la The Handmaid's Tale, and yes, you could see significant revolt from the disaffected, though a lot of it would likely have to be underground. There will be way bigger fish to fry than just the crackdown on fantasy gaming.
Realisticallly, I don't think you'd see much happening at the federal level, except maybe for those aforementioned congressional hearings, which would have little direct impact. Mostly, I think it would play itself out at the local level, with local law-enforcement trying to prevent gaming and fantasy material from being sold, arresting the sellers etc. Likely, most of this would be overturned by the courts, though if it dovetails with the ritual-abuse allegations(which in OTL were given an oversized dollop of credibility by the judicial system), it could get pretty ugly.
I was thinking more natural economic forces, consumer behavior and an expanding social stigma collapsing the market and thereby wiping out D&D and TSR in the 1980s and undermining fantasy on the whole, rather than any federal case or legislation against it.