Jerry Brown was Governor of California from 1975-1983, the era of this song. Singer Jello Biafra may wish to rework it given that this politician regained the office in 2011.
Brown is made the narrator and makes like he’s setting up a fascist regime, complete with secret police and genocide.
This charge may be effective punk rock style rhetoric, though fascism is a specific allegation not likely to formally come to pass in liberal democracies such as the United States, which govern under a constitution and the rule of law, with free and fair elections, an independent judiciary and free press.
Fascism is a political system that seeks to mobilize people into a single, nationalistic political community, such as through a revolution. Getting there, which also includes building a self-sufficient national economy, requires a strong (dictatorial) leader and a powerful state that puts itself above the interests and human rights, even, of the citizens. Fascism has no problem attacking weaker states to spread their bad cheer.
The most infamous example of a fascist state is Nazi Germany.