This is literally the plot of Halo, the Earthen government goes full buck wild imperialist and fascist, by killing communists, subjugating worlds, suppressing all forms of speech and proletarian action, and becoming a full military Junta government… Which completely blows up in their face when they run into a MORE advanced fascist-imperialist power. All of a sudden humanity isn’t so gung ho anymore when they’re getting curb stomped by the Covanent.