今年上半年以来，美国逐步将海岸警卫队部署到南海。此举可能意味着中美在南海的“灰色地带”较量将成为常态。

早在2016年，美国国内就开始讨论将海警部署到南海，以应对中国的所谓“灰色地带”，即海上民兵和海警。近三年来，随着中美关系恶化和两国南海较量持续升级，这种讨论日益得到美国朝野的支持。今年3月美国海警“伯索夫”号巡逻舰穿越台湾海峡，5月美菲海警在黄岩岛附近海域开展七年来首次联合训练。6月底，美国海警太平洋地区司令费根明确表示，已在日本横须贺基地部署“伯索夫”号和“斯特拉顿”号两艘国家安全舰，用以加强南海沿岸国的渔业执法领域能力建设和帮助其海上“维权”，监视中国海上民兵武装，配合美军南海行动。至此美国将海警部署到南海的决策一步步明朗。值得注意的是，美国海警从缺少预算到正式进入南海，显然已经得到国会、五角大楼和白宫的支持。种种迹象都表明，美国海警部署到南海将逐渐常态化。

国际社会普遍认为，部署海警是美国再次升级南海军事行动的举措。但事实恐怕不仅于此，此举还预示着美国正在调整其南海政策。

一是政策方式正在由以硬实力、硬对抗为主，转变为软硬兼施、软力量和软对抗占主要地位。过去的两年里，美国南海政策的主线是以航行自由行动压制中国。美军舰机在南海穿（飞）越本质上是一种武力展示，其背后逻辑是“强权即公理”的硬实力对抗。相较而言，海警作为执法力量，虽被称为“准军事力量”，但实质仍是一种“软力量”。换言之，双方海警南海较量的重点将由“谁的力量更强”，转变为“谁能说服国际社会相信自身的法理主张更合理”。当然，美国并不会放弃以海空力量作为威慑的政策选择，但这种方式将逐渐成为背后的威慑力量。

二是美军在南海的政策目的正从过往的以遏止中国力量扩张、保持地区力量分布中的压倒性优势为主，转向既要维持力量压倒性优势，又要确保在南海地区的长期稳定存在。相较于强大的海空军，海警的力量显然稍逊一筹，但其部署和行动预算开支及政治外交风险相对较低。此一点既符合特朗普上台以来降低全球霸权成本的计划，有助于美军实现在南海的长期稳定存在，也可以维持美国在南海地区与中国的“军事平衡”。

三是政策实践逐步由单边主义向双边和多边主义转变。2010年以后，美国前后两届政府都一直寻求以多边和双边主义遏制中国在南海的“扩张”行动。特别是特朗普上台以来，一直在推动菲律宾、澳大利亚、日本、韩国、英国等域内域外盟友参与南海联合航行自由行动。但出于各自的战略考量和利益诉求，各方并未参与美方行动，而是采取“迂回策略”，通过自主的单边海上行动予以配合和支持。但美国以海警作为合作对象，降低了联合行动的敏感性，大大消除了其盟友和伙伴国的顾虑，也提高了联合行动倡议的可操作性。目前，美国不仅已与菲律宾建立海警合作关系，还与越南开展海警部门间的交流，如向越南提供24艘海警船、海警部门间访问等。借助海警部门间的联合训练、力量建设、维护航道安全和环境保护等领域的合作，以执法和维护公海自由的名义，美国有望实现与区域内外国家间的双边和多边联合行动。

伴随美国海警在南海的常态化存在，中美之间围绕海警的“准军事”较量无疑将日趋频繁，而两国在南海全面竞争和对抗的态势也将继续恶化。

其一，随着美国常态化、强化在南海的海警力量部署，美国海警与中国海警和海上渔民（船）的纠缠势必增加。目前美方已经明确，它在横须贺基地两艘船的主要目的之一就是监视中国海上民兵。因而，中国海警在南海断续内海域，尤其在仁爱礁、黄岩岛、铁线礁、琼台礁等岛礁附近海域的巡航执法行动，以及渔民船只在南海传统渔场的捕鱼活动，都将遭到来自美国海警船的干扰。需要警惕的是，中美海警尚缺乏类似海军部门之间的海上相遇规则，一旦相遇还将面临如何保持自我约束、规范行动、有效沟通等一系列难题，发生误判和不测事件的可能性较大。其二，随着美国海警以执法名义进入南海，中美在南海的法理较量将逐步加剧。特别是美国认为中国应该遵守菲律宾南海仲裁案裁决，但中国奉行“不接受、不参与、不承认”的政策。未来，两国海警在南海行动的矛盾首先将是“谁的行动和存在更具有法理依据”，双方南海法理较量将逐步凸显并日陷焦灼。其三，美国利用海警编织的合作网络与中国在南海的竞争将加剧。就目前而言，菲、越、日、澳等域内外国家都倾向于支持仲裁裁决和美军在南海的行动。美国将利用海警合作构建一个以中国为反制对象的联盟和伙伴国网络，中美南海互动将愈加陷入带有冷战色彩的对抗之中。

Since the first half of this year, the United States has gradually deployed its Coast Guard to the South China Sea, portending the normalization of the gray area contest between China and the United States.

In 2016, the United States discussed the deployment of its Coast Guard to the South China Sea to deal with China's gray areas, namely the maritime militia and coast guard. In the past three years, with the deterioration of China-U.S. relations and greater competition between the two countries in the South China Sea, this move has gained support. In March, the U.S. Coast Guard Cutter Bertholf sailed through the Taiwan Strait. In May, U.S. and Philippine coast guard forces held an exercise in the waters near Huangyan Island for the first time in seven years. Then, in late June, U.S. Coast Guard Pacific Area Commander Linda Fagan said that Coast Guard Cutters Bertholf and Stratton had been deployed in conjunction with other U.S. military vessels in Japan's Yokosuka Naval Base to help law enforcement in the South China Sea and capacity-building in the fisheries enforcement realm, as well as to monitor China's maritime militia. All this lays bare the U.S.'s intention to deploy its Coast Guard to the South China Sea. It is worth noting that the U.S. Coast Guard has received financial support from Congress to the Pentagon and the White House to enter the South China Sea. These are indications that the deployment of the U.S. Coast Guard to the South China Sea will become the norm.

The international community generally believes that the deployment of the U.S. Coast Guard is meant to upgrade U.S. military operations in the South China Sea. It may also indicate an adjustment to the U.S.'s South China Sea policy.

First, the U.S. is shifting from an approach that uses hard power and confrontation to one that uses soft power plus select hard measures, as well as some purely soft power and confrontation. In the past two years, its main policy line has been to suppress China's freedom of navigation. The use of American warships and aircrafts in the South China Sea is a kind of force display, the logic being that might is right. In comparison, the coast guard, as law enforcement, is a paramilitary force, but it still is essentially soft power. In other words, the focus of the contest between the two sides in the South China Sea will shift from who is stronger to whose legal principles are more reasonable to the international community. Of course, the United States will not abandon its use of sea and air power as deterrents, but this approach will be a deterrence from behind.

Second, the policy objectives of the U.S. military in the South China Sea are shifting from curbing China's power expansion and maintaining the U.S.'s regional power advantage to maintaining its overwhelming advantages in force and ensuring its long-term stable presence in the South China Sea. Compared with U.S. naval and air forces, the U.S. Coast Guard is obviously inferior, but its deployment and operational expenses and diplomatic risks are relatively low. This is in line with President Trump's plan to slash global hegemonic costs while still helping the U.S. military achieve a long-term stable presence in the South China Sea and maintaining the U.S. military balance with China in the region.

Third, the country's policy has gradually transitioned from unilateralism to multilateralism. After 2010, both Obama's and Trump's administrations have sought to contain China's expansion in the South China Sea with multilateral and bilateral tools. Since Trump took office, he has encouraged allies such as the Philippines, Australia, Japan, South Korea, and the United Kingdom to participate in joint freedom of navigation exercises in the South China Sea. However, due to their respective strategic considerations and interests, the countries instead adopted a roundabout strategy to work with the United States through independent unilateral maritime actions. However, the United States has successfully used cooperation between coast guards to reduce the sensitivity of joint operations, eliminating a great concern of its allies and partner countries. At present, the United States has not only established a cooperative coast guard relationship with the Philippines, but it has also conducted exchanges with the Coast Guard in Vietnam. The United States provided Vietnam with 24 coast guard vessels and enabled exchange visits. Through joint training, strength building, maintenance of waterway safety, and environmental protection between Coast Guards, the United States can be expected to achieve joint operations with countries within and outside of the region in the name of law enforcement and the maintenance of freedom of the high seas.

Along with the normal presence of the U.S. Coast Guard in the South China Sea, the paramilitary contest between China and the United States around coast guards is likely to continue, possibly deteriorating into full competition and confrontation.

With the strong and regular deployment of the U.S. Coast Guard in the South China Sea, the entanglement between the coast guards and fishing boats at sea is bound to increase. At present, the United States has clearly stated that the primary purpose of the two ships at the Yokosuka base is to monitor China's maritime militia. Therefore, the U.S. Coast Guard may interfere in the China Coast Guard's cruise enforcement activities in the inner waters of the South China Sea, especially in the waters near Ren'ai Reef, Huangyan Island, Tiexian Reef, and Qiongtai Reef, as well as China's traditional fishing activities in the area. It should also be noted that the two countries' coast guards still lack rules for maritime encounters like those that have been established for encounters between the navies. Once they meet, they will face difficulties in how to maintain proper identification, self-discipline, standardized actions, and effective communication.In addition, with the U.S. Coast Guard entering the South China Sea in the name of law enforcement, the legal contest between China and the United States in the South China Sea will gradually increase. In particular, the United States believes that China should abide by the South China Sea arbitration with the Philippines, but China does not accept, participate in, or recognize it. In the future, the conflict between the U.S.'s and China's coast guards in the South China Sea will be based on which side has greater legitimate legal basis for its actions and presence.Finally, the competition between the network of regional coast guards will intensify. For now, countries inside and outside the region such as the Philippines, Vietnam, Japan, and Australia, tend to support the arbitral award and the U.S. military's actions in the South China Sea. The United States will continue use coast guard cooperation to build a network of alliances and partner countries that target China, meaning that China-U.S. interactions in the South China Sea will increasingly resemble a Cold War-style confrontation.