In the 1904 case of Rassmussen v. United States, Jens Rassmussen was convicted for manslaughter in Alaska and appealed his conviction to the Supreme Court on grounds that he had been tried by a six-person jury instead of a twelve-person one as guaranteed by the Sixth Amendment. The court ruled against him, stating that not all constitutional rights apply to territories acquired by the U.S., such as Alaska at this time. This decision established what is known as "the doctrine of incorporation," which holds that certain protections afforded under the Bill of Rights do not necessarily extend to residents or citizens residing in U.S territories unless expressly granted by Congress.

In the dissenting opinion for Rassmussen v. United States, Justice Harlan argued that Alaska was incorporated into the U.S., and thus its residents were entitled to all constitutional protections. He disagreed with the majority's view of a distinction between incorporated and unincorporated territories, asserting that once a territory is part of the U.S., it should not be treated differently from any other state in terms of rights and liberties under the Constitution. He contended that this principle applied regardless of whether Congress had made specific legislation to "incorporate" it or not. The justice expressed concern about denying full constitutional rights to American citizens based on their residence in newly acquired territories, arguing such denial contradicted America’s democratic principles.