Rosenblatt v. Johnston was a United States Supreme Court case that addressed the issue of whether a state court could issue a writ of mandamus to compel a federal court to act on a case. The case involved a dispute between two parties over a contract for the sale of a steamboat. The plaintiff, Rosenblatt, had filed a suit in the federal court to enforce the contract, but the defendant, Johnston, had filed a motion to dismiss the case. The federal court had not yet ruled on the motion, and Rosenblatt sought a writ of mandamus from the state court to compel the federal court to act on the motion. The Supreme Court held that the state court did not have the authority to issue a writ of mandamus to compel the federal court to act on the motion. The Court reasoned that the state court did not have the power to interfere with the proceedings of the federal court, and that the writ of mandamus was an inappropriate remedy in this case. The Court also noted that the federal court had the power to dismiss the case on its own, and that the state court should not interfere with the federal court's decision-making process.

Justice Field delivered the dissenting opinion in Rosenblatt v. Johnston, arguing that the majority had incorrectly interpreted the law and failed to consider relevant evidence. He argued that under California's Civil Code of 1872, a contract was formed when an offer was accepted by both parties and consideration exchanged - which he believed had occurred in this case. The plaintiff offered to purchase land from defendant Johnston for $2,000; Johnston accepted with certain conditions attached; and consideration (the payment of money) was exchanged upon acceptance. Justice Field further noted that there were no other requirements specified by statute or common law as necessary for a valid contract formation at this time in California history. Therefore, he concluded that the lower court should have found a binding agreement between Rosenblatt and Johnston based on their exchange of offers and acceptances along with consideration paid by Rosenblatt.