It is one of the Civil War amendments. But like the rest of the constitution it is written in a way that allows its application to future events. I suspect this issue will work its way to the Supreme Court fairly quickly.
There is some irony in the fact that the authors of the article I linked to in my opening post are conservative constitutional law professors (members of the Federalist Society) who analyze the matter from an originalist perspective. It is ironic but not surprising. In general conservative judges (some appointed by very poorly chosen one) have been steadfast in their application of constitutional principles in response to litigation that has arisen from the events surrounding the 2020 elections. The appeals court panel that ruled in the Cawthorn case was unanimous and included a trump-appointed judge.