Notably neither the Constitution nor its Amendments is the “social contract.”
It doesn't constitute a "contract" any more than a schoolyard bully demanding another child's lunch money "or else" (implicit threat of initiation of force / violence) constitutes a "contract".
The bully wouldn't become morally justified by calling his dictated orders (under threat of violence) a contract, nor would his act of extortion become any more legitimized, by deceptively referring to the act with an unambiguously incorrect term like "contract".
A contract you cannot choose to decline, and that you'll face imprisonment for violating isn't really a contract at all, it's really just a set of orders being dictated to you by a tyrant willing to initiate violence to get their way.