Biden? I think committing a fucking genocide against a native population (even bypassing congress to do so) and supporting a fascist government is "becoming more and more fascist" enough.

The two-party system is just the two sides of the US's imperialism coin. Anyone elected through it showing even the slightest hint of anti-imperialist sentiment (like JFK for wanting to abolish the CIA and giving an anti-colonial speech) is gotten rid of and replaced.

Like all capitalist political systems, it is specifically designed to prevent leftward movement; that can only happen by organizing outside the system.