幾乎所有南海地區之沿海國均已批准了「一九八二年聯合國海洋法公約」；中華 民國、泰國及高棉是例外。上述南海地區之沿海國大都依照一九八二年海洋法公約之規定制 訂其國內海洋立法，舉如宣布十二海里領海和兩百海里專屬經濟區範圍，以及制訂通過領海 暨專屬經濟區法等。一九九七年十二月與一九九八年六月，中華民國與中共各自分別制訂通 過專屬經濟區與大陸礁層之國內立法。南海周邊國家之海洋立法與一九八二年海洋法公約兩 者間仍有出現相左的地方。此些相異的規定被稱之為「越權之海域主張」，其中包括越權的 直線基線劃法、軍艦進入通過領海須事先獲得許可規定、歷史性海灣或歷史性水域主張等。 自一九七九年以來，美國透過「航行自由方案」之執行，對全球各地「越權之海域主張」作 出挑戰反應。本文目的在探討美國針對南海地區中共、中華民國、菲律賓、越南與高棉之歷 史性水域主張所作出之反應。本文之結論是，一旦美國在南海地區之航行自由和飛越權利之 行使受到中共或其他國家越權海域主張所阻礙，美國勢必作出強硬之反應。本文亦指出，倘 若美國加入一九八二年海洋法公約，其對越權海域主張所採之挑戰抗議行動更有說服力和適 當性。

　　　　　Nearly all the coastal states in the South China Sea area have ratified the 1982 United Nations Convention on the Law of the Sea (1982 LOSC), with the exception of the Republic of China (Taiwan, ROC), Thailand, and Cambodia. Most of the countries in the area have enacted domestic maritime legislation in accordance with the provisions contained in the 1982 LOSC. Which declare for instance a 12 nautical mile territorial boundary and a 200 nautical mile Exclusive Economic Zone (EEZ). The ROC and the People's Republic of China (PRC) enacted the Law on the Exclusive Economic Zone and the Continental Shelf in December 1997 and June 1998 respectively. However, there are discrepancies between maritime claims of the countries in the area and the 1982 LOSC. These discrepancies between maritime claims of the countries in the area and the 1982 LOSC. These discrepancies have been challenged as "excessive maritime claims", which include excessively straight baselines, and demand for prior permission for warships to enter territorial waters. Since 1979, the United States has responded to the "excessive maritime claims" in different parts of the world through the Freedom of Navigation Program. The purpose of this article is to study the U.S. reaction to the historic waters claims of the PRC, the ROC, the Philippines, Vietnam, and Cambodia. The article concludes that the United States would be forced to take action in response to the PRC's excessive maritime claims if freedom and rights of navigation and over-flight in the area were disrupted by the claimants. This article also concludes by suggesting that the United States should join those challenging these "excessive maritime claims."