Badger v. Ranlett was a United States Supreme Court case that dealt with the issue of whether a party could be held liable for a breach of contract when the contract was not in writing. The case involved a dispute between two parties, Badger and Ranlett, over a contract for the sale of a horse. Badger claimed that Ranlett had agreed to purchase the horse for a certain price, but Ranlett denied that any such agreement had been made. The Supreme Court held that Ranlett could be held liable for breach of contract even though the contract was not in writing. The Court reasoned that the parties had agreed to the terms of the contract, and that the agreement was evidenced by the conduct of the parties. The Court noted that Ranlett had taken possession of the horse and had made payments on the purchase price, which indicated that he had accepted the terms of the contract. The Court also noted that Badger had relied on the agreement and had acted in a manner consistent with the agreement. The Court concluded that Ranlett was liable for breach of contract and ordered him to pay the purchase price of the horse. This case established the principle that parties can be held liable for breach of contract even when the contract is not in writing.

In Badger v. Ranlett, the United States Supreme Court was asked to decide whether a deed of land in Maine that had been given by an Indian tribe to a settler was valid and enforceable. The majority opinion held that the deed was not valid because it violated federal law prohibiting such transfers without approval from Congress. Justice Field dissented, arguing that there were no laws preventing Indians from transferring their lands as they saw fit and therefore the transfer should be upheld as valid under state law. He argued further that if Congress wanted to prevent such transfers then it should have passed legislation specifically prohibiting them rather than relying on general statutes which did not apply in this case. He concluded by noting that while he agreed with the majority's decision regarding other issues raised in this case, he felt strongly about protecting Native American rights when it came to disposing of their own property according to their own customs and traditions.