Western Massachusetts Insurance Company v. Transportation Company was a case heard by the United States Supreme Court in 1871. The case involved a dispute between the two companies over a contract for the transportation of goods. The insurance company had issued a policy to the transportation company, which provided coverage for any losses incurred during the transportation of goods. The transportation company then entered into a contract with a third party to transport the goods, but the goods were lost during the journey. The insurance company refused to pay the claim, arguing that the contract with the third party was not covered by the policy. The Supreme Court ruled in favor of the insurance company, finding that the contract with the third party was not covered by the policy. The Court held that the policy only covered losses that were directly related to the transportation of goods, and not losses that were caused by a third party. The Court also noted that the policy did not provide coverage for any losses that were caused by the negligence of the transportation company. This ruling established the principle that insurance policies must be interpreted in accordance with their plain language, and that any losses that are not explicitly covered by the policy are not eligible for coverage.

In the case of Western Massachusetts Insurance Company v. Transportation Company, Justice Field delivered a dissenting opinion in which he argued that the majority's decision was wrongfully based on an interpretation of state law rather than federal maritime law. He argued that since this was a contract between two parties involving interstate commerce, it should be governed by federal maritime law and not state common-law principles as determined by the majority. Furthermore, Field noted that even if one were to accept the majority's interpretation of state law, their conclusion would still be incorrect because they failed to consider all relevant factors when determining whether or not there had been any breach of contract. In his view, both parties should have been held liable for damages due to their respective breaches and thus each party should bear its own losses from this transaction instead of having them shifted onto one side only as decided by the court’s ruling.