Evidence for the Republican party becoming more authoritarian:

- attempted illegal book bans

- suppression of right to protest and free speech on university campuses with lawfare

- US citizens being black bagged and deported to foreign concentration camps without due process and against court rulings

- deploying the army to the states unconstitutionally

- continued gerrymandering over the ruling of state supreme courts (Ohio)

Evidence for the Democratic party becoming more extreme:

- ... I'm struggling to think of an example, maybe you hold that prosecution of violent insurrectionists and their ring leader, the current president, was political extremism and authoritarian, but one would be so far detached from the reality-inhabiting community if so I don't know what to tell you.