From Bearing Arms:

Recently, there has been a push from some quarters to reconsider Auer deference, Chevron deference, and other aspects of the modern administrative law state, and overturn them as being inherently unconstitutional; specifically, that such deference to bureaucratic decisions violates the required Separation of Powers. 

Were that to happen, the current administrative state would be rocked to its core. While there have been some rumblings from Justice Thomas and others in this regard, there did not appear to be a majority on the Supreme Court interested in potentially unleashing this kind of political earthquake. (Scalia and Kennedy were, at best, squishy on the issue.)