The setup. 5 to 10 AI players. A few are secret spies who know each other. Everyone else is loyal Resistance and knows only their own role. You can watch blind, or flip See spies to know who is lying.
Each round. The leader picks a mission team of a set size. Everyone then votes to approve or reject it in public. If more than half approve, the team goes on the mission. Otherwise leadership passes to the next player and a new team is proposed.
On the mission. Team members secretly play success or fail. Loyal players can only ever succeed, so a single fail card sinks the mission. (Mission 4 needs two fails in a 7+ player game.)
Winning. First side to 3 missions. Resistance need 3 successes, spies need 3 fails. The spies also win instantly if 5 teams in a row get rejected, so voting no forever is not a safe strategy.
What to watch for. Every team, vote, and result is public, so the loyal players can reason about who must be lying. A failed mission implicates everyone who was on it. Good spies pass a mission or two to buy trust before they strike.