It's preamble is a definition of that social contract.
You want to prove: The Constitution is not a social contract.
You claimed that :
"-- I'll smash your definition, sending you back to square one. --"
Smash away Izzy.
Our Constitution is a social contract. It's preamble is a definition of that social contract.
You claim it's a social contract. You want to prove it. You need to do more than repeat the claim over and over. If you say the constitution is a social contract, and then you say a social contract is the constitution, you are going around in a circle.
If you want to prove that the Constitution has legitimate force over me, then there's another thing you can't do. You can't point out that the Constitution says it does. The question is, where does it get the authority to go saying it's got that authority?
If you try to use that argument, I'll answer that the Bible has authority over you. I'll prove it by quoting the Bible verses that say so. Then I'll force you to adopt my religion. Salt to taste. Serve with red wine.