Edwin M. Chaffee brought a case against the Boston Belting Company to recover damages for breach of contract. The court found that there was an agreement between the parties, but it was not in writing and therefore could not be enforced by law. However, since both parties had acted on their agreement and relied upon its terms, the court held that Chaffee should receive compensation from Boston Belting Company for his losses due to their breach of contract. In doing so, they established what is now known as promissory estoppel: when one party makes a promise which another relies upon and acts accordingly even though no written document exists to enforce it, then if one party breaches this promise they are liable for any resulting damage or loss suffered by the other party.

In the case of Edwin M. Chaffee v. The Boston Belting Company, the dissenting opinion argued that a contract between two parties should be enforced as written and not interpreted in favor of one party over another. Specifically, it was argued that when an agreement is made for payment in installments with no provision for acceleration or forfeiture if payments are missed, then any installment payments due must be paid before any other claims can be considered valid against the debtor's property. Furthermore, it was argued that even though there may have been some ambiguity regarding certain terms within the contract itself, this did not give either party license to interpret those terms however they saw fit; rather both parties were bound by their original agreement regardless of how difficult it might have become to fulfill its obligations at a later date.