What are the implications of establishing a judicial appointment mechanism for a separate constitutional justice? We look at the cases of Guatemala and the Dominican Republic. We study the contexts, processes, and reasons of constitutional reforms in both scenarios. We conclude that constitutional assemblies choose mechanisms that represent their composition, as the theory of Brinks and Blass suggests. Moreover, we see that the length of tenure and separating the appointments in stages is something that the Dominican Republic has done better than Guatemala, but Guatemala deserves attention for achieving high independence and supremacy in a short period of its history.