The tale of Trump's presidency starts with the promise of a wall to defend the country against a fantasy 'other' and ends with the necessity of a wall around the country's capitol to defend it from his own supporters. That's where the politics of paranoia ultimately leads you.

Why? Because if you invoke an existential threat to the group, then you equally begin to position those who don't join with you as betraying the group and colluding in its destruction. The enemy without creates accusations of an enemy within.

Once your opponents are no longer seen as part of the group (we the patriots, they the traitors) then one cannot accept them as representatives of the group. Their victory in elections is necessarily illegitimate, a theft by those unentitled to office from those who are entitled.

That, rather than any technicalities about votes, is the basis of the theft claim. It's not that defeat isn't true but that it cannot be true. And like weapons of mass destruction, the evidence must be there even if you can't find it.

Once enemies have taken power in your country, you cannot accept that and remain a patriot. You are obliged to claim it back in order to retain your own place in the group. And that's why non-scaleable barriers are necessary in Washington today.
A cautionary tale.