That's exactly what it is. The machinery is even the same. Point to errors in process, which are/were not reversible errors as a way of clouding the facts, further cloud the facts by nitpicking evidence that for the most part is immaterial, and make
ex post facto claims about unscrupulous witnesses, recanted testimony, and hearsay, long after people are dead or no longer compelled under threat of perjury.
Sacco and Vanzetti is the very template for turning murder convictions into a political game.