Bullard v. Bank was a United States Supreme Court case that dealt with the issue of whether a bank could be held liable for a breach of contract. The case involved a dispute between a bank and a customer, Bullard, who had deposited money with the bank. Bullard claimed that the bank had breached its contract with him by failing to pay him the interest due on his deposit. The Supreme Court held that the bank was liable for the breach of contract. The Court reasoned that the bank had a duty to pay the interest due on the deposit, and that the bank had failed to fulfill that duty. The Court also held that the bank was liable for any damages that Bullard suffered as a result of the breach. The Court's decision in Bullard v. Bank established that banks can be held liable for breaches of contract. This decision has been cited in numerous subsequent cases, and it has been used to support the idea that banks must be held accountable for their contractual obligations.

Justice Field delivered the dissenting opinion in Bullard v. Bank, arguing that the majority's decision was contrary to established precedent and would lead to a dangerous expansion of judicial power. He argued that under existing law, courts were not authorized to set aside contracts between parties on equitable grounds unless there had been fraud or mistake involved in their formation. In this case, he noted that no such allegations had been made by either party and thus it was inappropriate for the court to interfere with what amounted to an ordinary contract dispute between two private entities. Furthermore, Justice Field warned against allowing judges too much discretion when deciding cases involving contractual disputes as this could lead them down a slippery slope where they might be tempted into making decisions based upon personal bias rather than legal principles.