미국 연방헌법 수정증보 제4조의 압수 및 수색의 범위에 관한 고찰 ― 연방법원 판례의 동향을 중심으로 ―

The Fourth Amendment to the U.S. Constitution stipulates the prior warrant principle in search and seizure for investigative purposes. Although the U.S. Constitution does not specify the right to privacy, the Fourth Amendment setting out the principle of a prior warrant to prohibit unfair search and seizure, is the basis for protecting individual tranquility - the right to be alone, the privacy of space - from arbitrary intrusion of police power. In the 2012 United States v. Jones decision, the Supreme Court has extended the scope of the Fourth Amendment to prohibit the government from GPS monitoring and tracking of suspect vehicles and collecting personal location information by GPS devices. In particular, in Carpenter v. United States of 2018, the Supreme Court found that the investigation of past location data by collecting cell-site location information without search warrants violated the Fourth Amendment. The Supreme Court maintained a very cautious attitude in applying the Fourth Amendment. In short, there are two main streams in federal courts precedents regarding the actions of investigative agencies to acquire spatial and location information, which can be viewed as the search and seizure under the Fourth Amendment which requires a prior warrant. The first stream is the trespass property theory. According to it, there must be a physical intrusion that causes privacy infringement in order for the search and seizure to fall under the prior warrant principle under the Fourth Amendment. For example, in the Olmstead decision of 1928, the Supreme Court concludes that the Fourth Amendment does not apply to ‘wiretapping’ for it cannot be considered a search and seizure. This is the position of traditional precedents and is based on Boyd decision of 1886. The second stream is the Katz Test, as known as the reasonable expectation of privacy theory. As the protection of privacy, not property, was considered as the goal of the Fourth Amendment protection, the reasonable expectation of privacy theory was established in Katz after the Warden decision. While the mainstream of the Supreme Court has been dependent on the reasonable expectation of privacy theory since then, recently the Supreme Court has handed down United States v. Skinner which seems to be repugnant to this trend. In this regard, it is necessary to take an in-depth look at the United States v. Skinner decision. The precedents of the Supreme Court and federal courts of U.S. regarding search and seizure under the Fourth Amendment can give us significant implications in relation to the Korean Constitutional Court's decisions regarding the cell-site location information.