Somebody asked on the Objectivism subreddit:

Would it be right to have a constitution you couldn’t change? Even if [that constitution] was right?

For example. If a constitution was written and it banned taxes, had free speech, right to bear arms. And basically did everything perfectly and was unchangable no matter how many votes there was [sic]. Would this still be right? Or would this actually be wrong?

Here’s my answer:

It would be deeply wrong.

Following philosopher Karl Popper, we should judge political institutions not by their prophetic ability to guarantee any specific preconceived outcomes, but by how well they facilitate error correction.

Constitutions are written by people, and people are fallible, meaning we should expect even our best political documents to contain mistakes. Sooner or later, even a seemingly perfect constitution requires changing to correct errors. There’s no authoritative criterion for perfection anyway.

A political institution that prevented the correction of errors would be immoral since it would forcibly entrench the status quo. Just imagine you set up such an institution, and then you do find an error – then you’re either stuck with that error forever or people eventually resort to violence and revolutions to correct it.

For example, I agree that taxes should be banned and that speech should be free, but I could be wrong about that. And if I am wrong about that, I wouldn’t want to be stuck with that mistake. One of the defining political achievements of the West is that, contrary to ~all preceding human history, its political institutions do not entrench mistakes but facilitate their correction.

It’s worth noting that some Western countries still have partly unchangeable constitutions. The German constitution, for example, contains two articles that must never be changed. The first of those two states that human dignity is (or rather, shall be) inviolable. I understand this article was written in response to the horrors of WW2. I’m not sure if there’s literally no constitutional mechanism to change or get rid of this article, but even if there is, that would presumably be exceptionally difficult on purpose.

For the reasons I explain in my answer above, immunity to change is a mistake. In this instance, it’s based on good intentions, but it’s trying to build on allegedly secure, infallible foundations. What if, one day, this article about human dignity, as great as it sounds now, is found to be mistaken? Or what if it’s found to be in conflict with another part of the constitution (as I believe it is) in such a way that it’s not obvious which part should prevail?