The Siren was a case heard by the United States Supreme Court in 1871. The case involved a dispute between the owners of the steamship Siren and the owners of the steamship City of New York. The Siren had been damaged in a collision with the City of New York, and the owners of the Siren sought to recover damages from the owners of the City of New York. The Supreme Court held that the owners of the Siren were entitled to recover damages from the owners of the City of New York. The Court found that the owners of the City of New York had been negligent in the operation of their vessel, and that the negligence had caused the collision. The Court also held that the owners of the Siren had acted reasonably in attempting to avoid the collision, and that they were therefore entitled to recover damages. The Court also held that the owners of the City of New York were liable for the damages caused by the collision, regardless of whether the owners of the Siren had acted reasonably in attempting to avoid the collision. This ruling established the principle of strict liability for damages caused by collisions between vessels. This principle has been applied in many subsequent cases involving collisions between vessels.

In The Siren, the Supreme Court was tasked with determining whether a ship's captain had the right to detain and search another vessel on suspicion of piracy. In an 8-1 decision, the court ruled that he did not have such authority. Justice Field wrote a dissenting opinion in which he argued that it is within a captain's power to take action against suspected pirates if there are reasonable grounds for believing they are engaged in illegal activity. He further stated that this power should be exercised with caution and only when necessary, but nonetheless exists as part of his duty to protect those under his command from harm or danger. Field also noted that while Congress has enacted laws regarding piracy, these do not supersede common law principles allowing captains to act on their own initiative when faced with imminent peril at sea.