At first glance the criminal justice systems of Australia and the United States look strikingly similar. With common law roots from England, they both emphasize the adversary system, the roleof the advocate, the presumption of innocence, and an appeals process. Upon closer reflection,however, they appear starkly different. From both Australian and U.S. perspectives, the authorsexplore those differences, examining important features such as the exclusion of evidence, rules regarding interrogation, the entrapment defense, and the open nature of trials. The Article concludes with an analysis of the reasons for those differences, reasons that heavily relate back to the founding of the two nations and the drafting of distinictly dissimilar constitutions.