Now, the executive branch makes marginal adjustments to wide sweeping policies and purposefully allows them to be interpreted however need be, that trend largely starting with FDR as you say.
Or, maybe earlier. Like with Washington, Hamilton, the Necessary and Proper clause, and the First Bank of the United States. This stuff, and the attendant argument, have been with us since the beginning. It ebbs and it flows. Getting all Pepperidge Farm remembering a simpler time before FDR is an exercise in amnesia.