For more info, see: https://en.wikipedia.org/wiki/Sortition
For more info, see: https://en.wikipedia.org/wiki/Sortition
That in itself will likely devolve into an oligarchic structure.
How is sortition going to help? It should either also become an oligarchy, or simply be a dysfunctional government, or not actually have anything at all to do with this subject.
Though random samples and a large enough sample size, you can ensure that at least those in elected (sortitioned?) positions are not members of the oligarchy. Additionally, since sortition is much more efficient in selecting candidates, it's possible to replace some formerly unelected bureaucrats with sortitioned ones. Even if it's not perfect, it's still an improvement.
Your randomly selected police officer.. ;)
As for dysfunctional, depends what kind of people you want in the legislation. If you believe that the kind of people who want to gain power should not be in office, then running for office is a contra indicator for should be in office and you have to use random selection.
In practice, it's likely that a class of elite advisors will rise up whose only function is to provide guidance to the newly-appointed "official" representatives. They may not hold official office, but if they make all the decisions in practice, wouldn't you say they have the power?
But smaller sortition "modules" could still be put in place to augment or protect other mechanisms of democracy. A jury to add that witchhunt-spirit to the supreme court might not be the wisest idea, but something like randomized eligibility for the passive vote, maybe only in one of multiple houses, could probably help weaken oligarchic grip without severe disadvantage in other aspects.
Of course there's always the chance that your randomly elected leaders might then choose to do away with sortition.
https://github.com/LukeB42/psyrcd/blob/master/scripts/sortit...