The Eighteenth Amendment was the result of decades of effort by the temperance movement in the United States and at the time was generally considered a progressive amendment.
In a sales contract, the parties are the seller(s) and buyer(s) of the real estate, who are often called the principals to distinguish them from real estate agents, who are effectively their intermediaries and representatives in negotiation of the price.
This counter-offer, in the form of the Subcontract Agreement, usually contains additional and/or different conditions, general conditions and clauses than what the subcontractor's proposal/bid form contained. The subcontractor is free to accept or reject the Subcontract Agreement.