An all-powerful uniparty can do things like this:

    - deport or jail you without due process
    - ignore the law in service of its own ends
    - punish its enemies, pardon its allies
    - ignore the constitution
    - install loyalists in centers of power, oust dissenters
    - suppress media which challenges its hold on power
    - commit crimes
    - enrich its friends
    - declare its "plenary authority" to do the above

They would start to pardon criminals that conducted acts they like and fire the people that investigated those crimes. They would try to bring everybody to jail that oppose or upset them or have opposed them.

They win when challengers become too rare because others are afraid of the consequences to oppose.

What the Trump administration did regarding the Capitol storming on January 6th tells you everything you need to know. They strive for power and nothing else.

I believe you're trying to say the real oppressors were liberals and ideas like people having civil rights that were enforced were somehow oppressing others. Look at what Republicans are doing in reality right now that they're in charge in the us, they're doing all the things that you're worried about.