In fact, Santorum is essentially limited to talking about US Postal Service (Clause 7 of Section 8) where domestic issues are concerned, most other federal government services that citizens think are bona-fide federal services, like SS and Obamacare Democratcare, actually constitutionally indefensible imo.
I am aware of it but not being scholarly or even barely educated, I always want ammunition so I can show it to others.
I need to read the entire Constitution a bunch of times. I am anxious for the fedgov be whittled down - no, that sounds too slow - sliced down - to only the duties allowed in the Constitution.