In the case of Grand Tower Company v. Phillips et al., the Supreme Court of the United States was asked to decide whether a contract between two parties was valid and enforceable. The contract in question was between Grand Tower Company and Phillips et al., and it involved the sale of a steamboat. The contract stated that the steamboat was to be sold for a certain amount of money, and that the payment was to be made in installments. The Supreme Court held that the contract was valid and enforceable. The Court noted that the contract was clear and unambiguous, and that the parties had agreed to the terms of the contract. The Court also noted that the contract was supported by consideration, meaning that each party had given something of value in exchange for the other's promise. The Court also held that the contract was not voidable due to any lack of capacity on the part of either party. The Court noted that both parties were competent to enter into the contract, and that the contract was not unconscionable or otherwise invalid. In conclusion, the Supreme Court held that the contract between Grand Tower Company and Phillips et al. was valid and enforceable. The Court noted that the contract was clear and unambiguous, and that it was supported by consideration. The Court also held that the contract was not voidable due to any lack of capacity on the part of either party.

Justice Field delivered the dissenting opinion in Grand Tower Company v. Phillips et al., arguing that the Court should have affirmed the decision of the Circuit Court and held that a contract between two parties was valid even though it had not been signed by both parties. He argued that, under Missouri law, an agreement could be enforced if there was evidence of mutual assent to its terms; this did not require signatures from both sides. The majority's ruling would effectively nullify any contracts made without written consent, which he believed went against established precedent and common sense. Furthermore, Justice Field noted that while some states may require signatures for certain types of agreements or contracts, such as those involving real estate transactions or wills, this case involved neither type of transaction and thus no signature requirement applied. In conclusion, Justice Field maintained his position that a contract can still be binding even when unsigned by one party if there is sufficient proof demonstrating mutual assent to its terms.