I’ve described this problem as the Free Parking Rule Paradox, although it’s not a paradox at all. The name just sounds good.
The same reasoning may apply to Secretary Sessions. He may simply conclude that although he disfavors the reasoning in Wickard, he will not place himself at a disadvantage in a framework where only his opponents can use the rule. If the law is as Wickard says, then he’ll play by that law, even though he favors a different outcome.
Or, he may simply adopt whatever reasoning advances his desired outcome with no regard for principles. Dunno. Yet.