Yes, I would be interested to hear his opinion on enumerated powers. I am of the mind that is question really should have said:
"If you think it's a good idea to have a national identity card, persuade your fellow citizens to pass a constitutional amendment allowing it."
If this is the best out of Scalia, who is purportedly the most "constructionalist" on the court then I fear for the Republic, as the saying goes. I don't want "constructionalists" on the bench, I want "literalists." I want someone who will read a part of the constitution that says "Congress shall make no law" and actually figure it to mean that Congress shall make no law on the subject. I don't know why a document in English actually needs interpreting. I speak it well.
Be careful with that common sense. The JBT fans will be after you. They will tell you that reading what a document actually says is "utopian".