Epistrophe
Etymology
From Greek epistrophḗ, "a turning about, a wheeling around," from epí ("upon, back") + stréphein ("to turn"). The image is of the sentence turning back to the same endpoint again and again. It is the tail-end counterpart to the head-end repetition of anaphora.
noun · /eh-PIS-truh-fee/
The repetition of a word or phrase at the end of successive clauses.
What it names
The hammer-blow closure of "of the people, by the people, for the people" — a refrain landing on the same words each time, so the ending sticks.
Example
She closed each paragraph with the same epistrophe — "and that is why it failed" — until the verdict felt inevitable.
Related idea
Anaphora repeats at the start of clauses; epistrophe repeats at the close. Combine the two around a phrase and you get symploce.