Hartford Fire Insurance Company v. Isaac Van Duzer was a case heard by the United States Supreme Court in 1869. The case centered around a dispute between Hartford Fire Insurance Company and Isaac Van Duzer, a New York resident. Van Duzer had purchased a fire insurance policy from Hartford Fire Insurance Company, and when his property was destroyed by a fire, he sought to collect on the policy. Hartford Fire Insurance Company refused to pay, claiming that Van Duzer had failed to comply with the policy's terms. The Supreme Court ultimately sided with Van Duzer, ruling that Hartford Fire Insurance Company had failed to prove that Van Duzer had violated the policy's terms. The Court held that the burden of proof was on Hartford Fire Insurance Company to show that Van Duzer had violated the policy's terms, and that the company had failed to do so. The Court also held that the policy's terms were ambiguous and that the ambiguity should be interpreted in favor of Van Duzer. The Court's ruling in this case established the principle that insurance companies must prove that policyholders have violated the terms of their policies in order to deny coverage. This ruling has been cited in numerous subsequent cases and has become an important part of insurance law.

In Hartford Fire Insurance Company v. Isaac Van Duzer, the Supreme Court was tasked with determining whether a fire insurance policy issued by Hartford to Van Duzer covered losses caused by a riot that occurred in New York City during the Civil War draft riots of 1863. The majority opinion held that the policy did not cover such losses because they were caused by an act of public enemies and thus fell outside of its coverage. In his dissenting opinion, Justice Field argued that while it is true that acts committed by public enemies are excluded from coverage under most policies, this exclusion should be interpreted narrowly so as to only apply when there is clear evidence showing intent on behalf of those committing the act or when their actions can be classified as warlike operations. He further noted that since no such evidence existed in this case and since there was no indication whatsoever suggesting any kind of military operation had taken place during these riots, he believed it would have been wrong for the court to deny coverage based solely on speculation about what may have happened during them.