What is the relationship and/or opposition between Aquinas' writings and Magisterium? That is, what can generally be said about using Aquinas to explain doctrine?
Or contrarily, does Aquinas stand in opposition to Magisterium such that his works cannot generally be used to explain or refine statements found in encyclicals?
This question: Are Catholics required to accept every article of Aquinas's «Summa Theologica»? does NOT answer my question. That question is about whether all parts of the Summa must be accepted (which is not quite but similar to "are all parts of the Summa magisterial?"). The answer was determined to be no and while the answers include substantial information around Aquinas', it doesn't answer what weight Aquinas has in relation to magisterial statements. i.e. In what case if any is the argument "that's substituting Aquinas for the Magisterium" reasonable or correct?