Denman dissented in Korematsu v. United States (9th Cir. 1943).[3] The Ninth Circuit permitted the government to force Japanese Americans into internment camps, and the Supreme Court affirmed the following year.
Denman wrote: "If it be unusual for a judge of a court in which he is a participant to dissent from his associates on the matter of a certification, the occasion is even more unusual.
Under the threat of penitentiary sentences to these 70,000 American citizens who have relied on the right they believe the Constitution gives them, we are driving from their homes to internment camps, not men alone, as with the deportation of the Dutch by the Germans, but their wives and children, without giving the latter the choice to remain in their homes. We are destroying their businesses, in effect, as if such citizens were enemy aliens. The destruction of their business connections means for many that they will not be able to return to their native areas; in effect, as were the French Canadians so taken to Louisiana."