The word “proper” wasn’t merely snatched out of thin air.
The Solicitor General brought up the Necessary and Proper Clause as relevant in addition to the Interstate Commerce Clause, as support for this mandate.
Scalia said it might be necessary to the scheme of the whole law, but that didn’t make it proper.
Proper in this case means constitutionally correct, rather than proper as in do you drink from your tea cup with your pinkie finger held straight, or crooked.
Context is everything.
There is nothing weak about Scalia’s replies to the Gov’t lawyer.
But, are the justices barred from opinion altogether? Can't they weigh in unreservedly and bring all THEIR judgment and understanding of the law to bear in the most articulate way possible?
Where is it written that they may not express an educated and informed statement apart from the exact language of the constitution?