The United States Supreme Court has ruled that the acquisition of cellphone location data by law enforcement agencies constitutes a search under the Fourth Amendment, thereby requiring a judicial warrant.

美國最高法院裁定，執法機關獲取手機位置數據屬於第四修正案下的「搜索」，因此需要司法搜索票據。

The adjudication in Chatrie v. United States centered on the legality of 'geofence warrants,' a mechanism whereby investigators compel technology providers to identify all users within a specified geographic radius during a precise temporal window. In the instant case, these methods were employed to identify Okello Chatrie following an armed robbery of a credit union in Virginia. The resulting data enabled the seizure of incriminating evidence, leading to Chatrie's conviction and a twelve-year sentence. The legal contention focused on whether the voluntary provision of location data to a third party, such as Google, nullifies an individual's expectation of privacy under the third-party doctrine.

Chatrie v. United States 案的審理核心在於「地理圍欄搜索票」（geofence warrants）的合法性。這是一種調查人員強制技術提供者識別在特定時間範圍內，處於指定地理半徑內所有用戶的機制。在本案中，此方法被用於識別 Okello Chatrie，因其在維吉尼亞州的一家信用合作社犯下武裝搶劫罪。隨後獲取的數據使得警方能查獲定罪證據，導致 Chatrie 被判處十二年監禁。法律爭議的焦點在於，根據「第三方原則」，個人將位置數據自願提供給第三方（如 Google）時，是否會使該個體對隱私的期待失效。

In a 6-3 decision, the majority, authored by Justice Elena Kagan, determined that location history functions as a comprehensive digital record of a user's movements, analogous to private journals or calendars. The Court reasoned that because the utilization of such services is often a prerequisite for device functionality, the act of opting into location tracking does not constitute a voluntary waiver of constitutional protections. Justice Sonia Sotomayor further noted that even brief monitoring can disclose sensitive associations, including religious, professional, or medical affiliations. Consequently, the Court held that the government must demonstrate probable cause to obtain a warrant for such data.

在一項 6 比 3 的裁決中，由大法官 Elena Kagan 撰寫的多數意見認定，位置紀錄是用戶行蹤的全面數位紀錄，類同於私人日記或行事曆。法院理由是，由於使用此類服務通常是設備運作的前提，因此選擇開啟位置追蹤並不構成對憲法保護的自願放棄。大法官 Sonia Sotomayor 進一步指出，即使是簡短的監控也能揭露敏感的關聯，包括宗教、職業或醫療相關的隸屬關係。因此，法院裁定政府必須證明有「合理理由」（probable cause）才能獲取此類數據的搜索票。

Conversely, the dissenting opinion, led by Justice Samuel Alito, characterized the ruling as an irresponsible departure from established jurisprudence. The dissent argued that individuals possess no reasonable expectation of privacy regarding their movements in public spaces and cautioned that the majority's approach could destabilize Fourth Amendment law by necessitating warrants for even the most innocuous data requests. While the Court affirmed the general requirement for warrants, it refrained from declaring geofence warrants inherently unconstitutional, instead remanding the specific case to the lower courts to determine if the warrant used in Chatrie's apprehension met the requisite legal standards.

相反地，由大法官 Samuel Alito 領導的少數意見將此裁決定格為對既有法理的不負責任背離。反對意見認為，個人在公共空間的行蹤並不具有合理的隱私期待，並警告多數派的做法可能會使第四修正案的法律失穩，因為這將導致即使是最無害的數據請求也需要搜索票。雖然法院肯定了搜索票的一般要求，但並未宣布地理圍欄搜索票本身違憲，而是將本案發回下級法院，以判定逮捕 Chatrie 時所使用的搜索票是否符合法律標準。

The Supreme Court has mandated that law enforcement obtain warrants to access cellphone location history, though the specific validity of the warrant in the Chatrie case remains for lower court determination.

最高法院已強制要求執法機關必須取得搜索票才能獲取手機位置紀錄，但 Chatrie 案中該搜索票的具體有效性仍有待下級法院判定。