I'm think there's a way for any coalition with bare majorities in the US Senate, House, Presidency, and at least one state government on a given day to establish de facto permanent rule by creating unlimited microstates.
Disclaimer: I'm not a lawyer or a constitutional expert of any kind, but this looks like a relatively straightforward exploit.
Here's how it would work: First, let's say some party dominates an election or two and ends up in full control of Congress and the White House, and is determined to keep the other parties out no matter what. Let's say it's the Bull-Moose party. An easy way to ensure this would be to create a lot of reliably-Bull-Moose voting states - each one gets you two Senators, a Congressperson, and three votes in the Electoral College. Enough of those and you'll have supermajorities forever.
To create a new state, all you need is a majority in both houses of Congress (and possibly presidential approval, but I'm not 100% clear on this part). If the new state you're creating is made of existing states, you also need the state(s) you're carving up to agree. And - that's it.
There's no reason a state can't be a quarter acre lot where one person lives.
So if the Bull-Moose party also controls, say, Idaho, the state can agree to create one thousay new microstates that each consist of the house of one Bull Moose activist, and Congress can approve it.
And here's the kicker: even if this outages the rest of the country and support for the Bull Moose party plummets, it doesn't matter - because even if everyone else votes against them, a few hundred die hard Bull Moosers in what was formerly a corner of Idaho will command supermajorities in the House, Senate, and Electoral College indefinitely.
It's probably worth noting that we're already living in a milder version of this world, with low-population states dominating the Senate, germanderred districts filling the House, and popular vote losers routinely winning the Electoral College. This just takes all the anti-democratic aspects of the existing system and turns them up so far that they can't ever be put back.
The moral of the story is that privileging certain votes above others based on arbitrary-as-fuck geographical boundaries is terrible and we should stop doing it. The Electoral College is awful and the Senate is awful and congressional-districts-especially-gerrymandered-ones are awful and moving towards a more democratic system that's less susceptible to this kind of fuckery might be a good idea.