Four of the eight members of the Mesa, which supervised books pertaining to theology and dogma, were not ecclesiastics. As the Mesa had jurisdiction over all printed materials, this included pastoral letters. Pacca made little headway against the entrenched institution.
Of the eight members on the Mesa, responsible for overseeing theological and doctrinal publications, four were not priests.  This encompassed their jurisdiction over all printed material, including pastoral letters. Despite Pacca's efforts, he was unable to overcome the entrenched power of the institution.