5月10日，美國軍艦第三次非法進入中國南沙群島有關島礁鄰近海域。儘管事實上美國的“航行自由計劃”已實施多年，且並非單獨針對中國，但是，我們仍需要根據1982年《聯合國海洋法公約》（以下稱《公約》）審視美國“航行自由計劃”的合法性，以了解其在建立以美國為主導的世界海洋法律秩序以及在實施“重返亞洲”戰略中的作用和反映出來的真正意圖。

為全面分析“航行自由計劃”行動的合法性，有必要回顧一下該計劃的歷史背景。在《公約》通過之前，“航行自由計劃”於1979年在卡特政府時期正式推出。根據美國國防部的情況介紹，“航行自由計劃”旨在保護美國的國家利益，反對有關沿海國的過度海洋主張。美國的“航行自由計劃”行動既包括外交溝通，也包括軍事宣示。按照美國的說法，該計劃對同盟的、友好的、中立的以及不友好的過度聲索國一視同仁。事實上當然不會如此。

儘管美國聲稱是為了“根據國際法捍衛所有國家的權利和自由”，但“航行自由計劃”行動的合法性在以下幾個方面仍然存在嚴重問題。首先，“航行自由計劃”違反了國際法關於和平解決爭端的基本原則。《聯合國憲章》第2條第三款以及《公約》第279條均規定所有國際爭端都應通過和平方式解決。對於《公約》的解釋和適用問題，各國持不同見解是一種正常情況。大多數國家會通過談判、斡旋、磋商等和平方式解決爭端，而美國是唯一一個無視自身國際義務、習慣性選擇軍事力量強行執法的國家。

其次，這種對抗性強的“航行自由計劃”構成“濫用權利”的行為，既違反了《公約》第300條的規定，也違反了“濫用權利”作為國際法淵源的一般原則。航行自由並不代表毫無限制的絕對自由。根據公約，世界海洋劃分為不同的管轄區域，不同區域適用不同的航行制度，比如適用於領海的無害通過制度、適用於國際航行海峽的過境通行制度、適用於群島水域的群島海道通過制度等等，這些航行制度下的權利和義務內容各不相同。基於美國自己而非國際社會公認的對這些航行制度的理解，美國在執行“航行自由計劃”行動時經常無視其國際義務，濫用航行權利。

更為明顯的是，美國“航行自由計劃”行動違反了“和平目的”或者“和平利用”海洋的原則，該原則在公約序言、公約第301條以及有關海洋多種用途的諸多條款中均有提及。當美國軍用艦機航行數千英里出現在沿海國家門口的領海附近以及專屬經濟海域，夜以繼日地進行收集情報和炫耀武力時，很難讓人認為此類威脅性行為是出於和平目的。就此而言，“航行自由計劃”行動是對沿海國家主權安全的公然威脅。視情況的嚴重性而定，“航行自由計劃”行動可能會同時違反《聯合國憲章》第2條第四款關於禁止在國際關係中威脅或使用武力的基本原則。

從沿海國管轄權的角度來看，“航行自由計劃”行動還違反了適用於不同管轄海域的沿海國國內法。以飽受爭議的軍艦行駛無害通過權為例，美國一貫主張，軍艦同商船一樣享有無害通過權是國際公認的一般國際法。事實上，這種典型的美國強權看法只為少數海洋強國支持，並沒有獲得國際社會的普遍認可。根據聯合國法律事務廳海洋事務與海洋法司提供的數據庫，至少有52個國家頒佈的國內立法限制軍艦無害通過權，方式包括要求預先通報、許可、批准或授權。這52個國家的數據本身就足以說明問題。行使無害通過權的“航行自由計劃”行動明顯違反了沿海國的國內法，這種違法行為不能僅僅因為美國自己對《公約》有不同理解而得到寬容。

美國“航行自由計劃”行動也違反了《公約》多處提及的“適當顧及”的義務。特別是，公約在序言中強調“適當顧及所有國家的主權”，公約第68條要求在專屬經濟區內活動的海域使用國“適當顧及沿海國的權利和義務”。對於在專屬經濟區內開展的“航行自由計劃”行動，執行任務的軍用艦機應適當顧及沿海國的權利與義務，並遵守沿海國的法律法規，尤其是有關海洋科學研究以及海洋環境保護方面的法律。事實上，為保護美國專屬經濟區內的海洋哺乳動物免受先進的軍事聲納設備的影響，美軍的很多軍事活動在其本國專屬經濟區內遭到禁止。美國將此類破壞環境的軍事活動轉移到其他沿海國家的專屬經濟區，這的確是一件很不光彩的事情。

有人可能會提出質疑，既然美國並非《公約》當事國，就不能以《公約》為標準來評價美國的“航行自由計劃”行動。這一問題的答案可以在美國對《公約》的態度中輕而易舉地找到。美國一直認為《公約》關於航行和飛越權的規定反映了國際習慣法。考慮到《公約》作為“一攬子”協議的性質，任何國家都不能只選擇適用那些對自己有利的條款，認為其反映了國際習慣法，而摒棄那些對自身不利的條款，認為其沒有反映國際習慣法。考慮到《公約》當事國的龐大數量以及統一的國家實踐，可以說上文提及的許多國際義務已成為國際習慣法，因而對包括美國在內的非當事國同樣具有約束力。

表面上看，美國的“航行自由計劃”行動是為了滿足其對世界海洋的私慾，它的唯一目的在於為其海空軍部隊提供最大的靈活性和機動性。實質上，通過強制執行美國眼中的國際法而無視國際公認的國際法，這類明顯具有挑釁性質的行動表明美國意欲實施霸權擴張，從而建立一個凌駕於以《公約》為保證的世界海洋法律秩序之上的由美國主導的海洋法律秩序。而具體到美國在中國南海執行的“航行自由計劃”行動，只不過是美國實施“重返亞洲”戰略的工具而已。

On May 10, the US warship illegally entered waters near the controversial reefs of China's islands in the South China Sea for the third time. It is true that the US Freedom of Navigation (FON) Program has been in place for many years, and it does not purport to target China alone. However, the lawfulness of the FON operations warrant examination in light of the 1982 International Law of the Sea Convention so as to know the role and intent of the FON Program in building a US-dominated world oceans legal order and in carrying out the “Pivot to Asia” policy.

A full analysis of the lawfulness of the FON operations necessitates a look back upon the program's historical background. It was formally instituted during the Carter administration in 1979 before the adoption of the convention. According to a fact sheet of the US Department of Defense, the FON program aims to preserve American national interest and demonstrate a non-acquiescence to excessive maritime claims asserted by coastal states. It includes both diplomatic communications and operational assertions. The US asserts that the Program impartially targets excessive claims of allied, friendly, neutral, and unfriendly states alike.

Despite the US claim “to uphold rights and freedoms of all states under international law”, the legality of the US FON operations can be challenged on several fronts. First and foremost, the program violated the general principle of international law to settle disputes peacefully. This principle is enshrined in both Article 2(3) of the UN Charter and Article 279 of the convention, both of which mandate that all international disputes are to be settled in a peaceful manner. It is not uncommon that states have different understandings with regard to interpretation and application of the convention. While most states choose to settle their disputes through peaceful means of negotiation, mediation and consultation, the US is the only country that habitually enforce its own will with warships and military aircrafts with blithe disregard for its international obligations.

Then, the confrontational FON program constitutes an “abuse of right” contrary to both Article 300 of UNCLOS and more generally under general principles of international law. The freedom of navigation does not mean absolute freedom without any restriction. Under the convention, the world's oceans are divided into various jurisdictional zones where different navigational regimes apply, such as innocent passage applied in territorial seas, transit passage applied in straits used for international navigation, archipelagic sea lanes passage applied in archipelagic waters, etc. The freedom of navigation comprises those various navigational regimes, the rights and obligations of which are quite different. Based on its own understanding of the terms of those regimes instead of those shared by international community, the US operations have often abused those navigational rights in defiance of international obligations.

For more apparent reasons, the US FON operations violated the principle of “peaceful purpose” or “peaceful uses” of the seas and oceans, which is stipulated in the Preamble，Article 301 and as well many provisions of the convention in relation to the various uses of seas. When advanced US warships and aircrafts travel across thousands of miles to the threshold of the territorial seas and EEZs of coastal states to conduct daily intelligence gathering activities and routine show of force, it is hard for anyone to take those threatening behaviors as being for peaceful purposes. The FON operations in this regard constitute a flagrant threat to coastal states' sovereignty and security. Depending on the seriousness of cases at issue, the US FON operations could simultaneously violate the fundamental principle of prohibition against the threat or use of force in international relations as embodied in Article 2(4) of UN Charter.

From the perspective of jurisdiction of coastal states, the FON operations also violated coastal states' national laws applied in various jurisdictional zones. Take the most controversial issue of exercise of innocent passage by warships for instance, while the US has always argued that the right of warships to innocent passage is generally recognized international law, it is typically American perspective shared by only a small group of major maritime powers in stead of by the international community as a whole. Based on the database provided by the Division for Ocean Affairs and the Law of the Sea of the UN Office of Legal Affairs, there are altogether at least 52 states that enact laws putting restrictions on the exercise of the right of innocent passage by warships, including prior notice, permission, approval or authorization. This figure of 52 states does speak for itself. The violation of coastal states' national laws with regard to innocent passage by FON operations cannot be tolerated by virtue of America's own understanding of the convention.

The FON operations are also inconsistent with the “due regard” obligation under the Preamble of the convention, which emphasizes “due regard for the sovereignty of all States”, and as well under Article 68, which requires the user states in the EEZ to have “due regard to the rights and duties of the coastal State”. For FON operations conducted in the EEZs, the warships and aircrafts shall have due regard to the rights and duties of the coastal State and shall comply with the laws and regulations adopted by the coastal State, in particular with regard to MSRs and marine environment protection. In fact, many of the US military activities have been prohibited in the US EEZ so as to protect the marine mammals from harms done by advanced military sonars. It is disgraceful to move those environmentally harmful military activities to the EEZs of other coastal states.

One may argue that UNCLOS could not be applied to judge the US FON operations since the US is not a party to the convention. The answer to this question could be easily found in the American stance with the convention, which has longed viewed the navigational and overflight rights it contains as reflecting customary international law. One cannot only pick up those articles of the convention to one's advantage as reflecting customary law and disregard inconvenient articles as not reflecting customary law. In terms of the high number of state parties to the convention and uniform state practice in this regard, the aforementioned obligations can be said to have become customary international law so as to also bind non-party states like the US.

On its face, the US FON program is an effort to assert US desires upon the world oceans for the sole purpose of affording its naval and air forces the maximum degree of mobility and flexibility. In essence, through enforcing American perspective of international law in defiance of shared international perspectives of international law, the apparent provocative nature of such assertions exposes the FON operations as exercises of hegemonic power projection so as to establish a US-dominated maritime legal order beyond a world ocean legal order guaranteed under the convention. As for the FON operations conducted in the South China Sea, they are no more than a tool to carry out the US “Pivot to Asia” strategy.