Writing for the Court, Chief Justice Fuller denied Kemmler’s writ and upheld New York’s statute instituting the electric chair as the state’s method of execution. Fuller began by establishing that the Eighth Amendment’s prohibition against cruel and unusual punishment doesn’t apply directly to state governments, since a restriction solely on the federal government. Therefore, for a state’s method of execution to be challenged in federal court, it must be shown to violate the Fourteenth Amendment’s protections of “due process of law” or the “privileges or immunities” citizenship. Regarding the Eighth Amendment, Fuller stated that while it can be used as a guide for what constitutes “cruel” conduct, a state law only violates the Fourteenth Amendment if it imposes a punishment that’s “inhuman and barbarous” or involves “torture or a lingering death”, such as burning at the stake or crucifixion.

On the use of the electric chair, Fuller deferred to the findings of the New York state legislature and courts, which had determined that execution by electricity was intended to be a more humane method of reaching the result of death. He noted that the New York courts found the method might be “unusual” because it was new, but it couldn’t be assumed “cruel” simply because it was a new technology. Fuller emphasized that the judiciary shouldn’t overturn legislative determinations unless there’s a clear need to. Ultimately, Fuller concluded that the enactment of the statute was a legitimate exercise of state legislative power and found no evidence that the state had violated Kemmler’s privileges or immunities as a U.S. citizen or deprived him of due process.