What is the test for making sense out of “true questions of jurisdiction”?

While trial judges wait to see whether appeal judges will “euthanize the issue” (Canada v. Canada, para. 41), we have to make some sense out of “true questions of jurisdiction”. I think that unless, as here, the decision-maker says “I do not have the power to make that inquiry.” we are beyond the purposes of deference and in a place where the rule of law and legislative supremacy demand correctness. Legislated decision-makers should not be able, by reasonable misinterpretation, to expand, or limit, their legislated powers. This, notwithstanding difficulty in definition, elusiveness of concept, imprecision, and other criticisms. A principle remains a principle even though it is difficult, elusive, and imprecise.