目前南海形势正处于阶段性动荡后的间歇期。鉴于美国大选引发“内斗”、政权进入过渡期、美国未来对外政策充满不确定因素，美国的南海军事行动有所放缓。而其他声索国对拜登政府南海政策的观望，以及难以预料中美未来在南海是斗是和，使之不敢贸然采取可能引发中国强烈反弹的单边侵权行动。在经历了2020年的阶段性动荡之后，2021年的南海形势将呈现出以下特点：

一是法理和规则领域的博弈将超越军事博弈，成为驱动南海形势发展演变的新主线。这主要是因为拜登政府将以裁决为依据否定中国在南海的权利和主张，对抗中国在南海的维权行动。“南海行为准则”磋商窗口期缩短，有关各方将谋求南海利益最大化，并试图通过“准则”予以确认和固化。

二是域外国家在南海的军事存在和军事行动将显著增加。除日本、澳大利亚之外，英国和法国将加入美军在南海的军事行动，亦可能联合采取针对中国的军事行动，如“联合巡逻”或“联合航行自由行动”。

三是声索国以巩固既得利益为导向的单边行动会比2020年有明显上升。比如，越南将以西沙侵渔、南沙油气开发为主要形式；菲律宾将以裁决为依据，以通过国内立法、执法、军事活动和拖延共同开发固化其非法主张为主要路径；马来西亚将在推动大陆架界限委员会审议其外大陆架申请、南康暗沙油气开发、琼台礁控制等方面表现得更加活跃和强势。

四是“准则”磋商将面临难以预料的困难。菲律宾、越南、马来西亚等国对”窗口期“延长的刚性需求、中国和东盟国家之间在核心条款上的分歧、域外国家对“准则”磋商的干扰、裁决和外大陆架申请案对“准则”的负面影响等，这些因素将在利益悠关方难以达成共识上充分显现出来。

五是由南海军事活动和准军事活动日趋密集引发的海上事件频发，使得制定覆盖域外域内国家军事和准军事活动的危机管控机制，比以往任何时候都显得必要和紧迫。

拜登执政初期，美国的南海政策不会出现大的调整，中美南海对抗的态势还会继续沿目前的轨道惯性发展。但随着中美政府间对话和沟通机制的恢复或建立，以危机管控为导向的对话、以法律斗争为主要内容的对抗和以扩大军事存在为目的的海上力量博弈，将是未来中美南海“竞合关系”的主要形式。

就美国与南海沿岸国的关系而言，在美国南海安全战略回归亚太安全战略框架的同时，美日、美菲、美越同盟伙伴关系的加强，可能会在一定程度上改变中国南海岛礁建设和设施部署形成的相对有利的战略态势。

拜登政府将利用《美菲加强防务协定》和重提仲裁裁决，迫使菲律宾在中美之间选边站，菲律宾可能再度成为南海问题的麻烦制造者。越南会因为美国在南海问题上继续对中国保持高压，而在美越军事基地使用和安全合作、争议地区油气开发、威胁提起仲裁等问题上走得更远。马来西亚则会因为美国的暗中支持，推动大陆架界限委员会审议其去年提交的外大陆架申请，并加快推进南康暗沙的油气开发。

最后，美国出于重回多边机制的战略需要，会给由中国主导的南海规则制定制造新的障碍，或是通过其东盟“代理人”从中作梗，从而使“南海行为准则”磋商陷入困境。

The current situation in the South China Sea can be described as a lull after the storm. The United States has slowed down its military operations against a backdrop of a contentious presidential election and transitional period afterward and the unpredictability of U.S. foreign policy in the future.Countries with maritime claims are less reckless about infringing China's rights and triggering backlash, as they are uncertain about the incoming U.S. administration's South China Sea policy and the interaction between the U.S. and China — whether it will be confrontational or peaceful in the future.After a turbulent 2020, the situation in the South China Sea in 2021 will be characterized by the following features:

First, competition in the legal and rule-making fields will take over military confrontation as the new trend. For the United States, the administration of the new president, Joseph R. Biden, will continue to deny China's rights to the South China Sea on the basis of the 2016 arbitral award.For other maritime claimants, the window is narrowing for code of conduct consultations as they seek to maximize their claims in the South China Sea and try to have their interests confirmed and consolidated.

Second, countries outside the region will substantially increase their military presence and operations in the South China Sea. In addition to Japan and Australia, the United Kingdom and France will join U.S. military operations there. They may jointly conduct military operations, such as joint patrols or joint “freedom of navigation operations.”

Third, compared with 2020, claimants will notably increase their unilateral actions to consolidate their vested interests. Vietnam, for example, will increase its disputed fishing in the waters of China's Xisha Islands and its oil and gas explorations in the waters of the Nansha Islands. The Philippines, based on the arbitral ruling, will mainly attempt to solidify its claims through domestic legislation, law enforcement, military activities and delays in joint development. Malaysia will become more active and assertive in pushing for deliberations by the UN Commission on the Limits of the Continental Shelf as applied to the development of oil and gas resources in the Nankang Ansha and in exerting control over Qiaongtai Jiao.

Fourth, the COC consultations will run into unexpected difficulties. The Philippines, Vietnam and Malaysia surely want the window to be extended before the conclusion of COC negotiations; China and some ASEAN countries have differences on some core clauses; some extra-regional countries may disrupt the consultation process; and the arbitral award and the CLCS submission will both have negative effects. All this will make it difficult for stakeholders to reach consensus on the COC.

Fifth, incidents on the sea will be triggered by more intense military and paramilitary activity in the South China Sea. This will raise the urgency and necessity to develop a crisis management mechanism covering countries inside and outside the region, as well as both kinds of military activity.Adjustment and impact of the U.S. South China Sea policy under the Biden administration

In the early days of the Biden administration, no major adjustments are expected in the U.S. South China Sea policy. China and the United States will continue their current confrontational dance, but with the establishment of dialogue and communication mechanisms between the two governments, a relationship of “coopetition” will emerge. This will feature dialogues focused on crisis management, confrontation (especially legal struggles) and competition for maritime power with the aim of military expansion.

As for its relations with other littoral states in the South China Sea, the United States will push its South China Sea security strategy again under its framework for Asia-Pacific security. At the same time, it will step up its military alliance with Japan, the Philippines and Vietnam. This to some extent will change China's relatively favorable strategic posture after its construction islands and reefs in the South China Sea and its military deployments there.

The Biden administration will pressure the Philippines to choose sides between China and the United States by leveraging the Enhanced Defense Cooperation Agreement (EDCA) and again emphasizing the arbitral award. Vietnam will go further on issues such as the U.S. use of its military bases and Vietnamese-U.S. security cooperation, oil and gas development in disputed areas and the threat to lodge its own arbitration case against China. The United States will continue its high-pressure policy toward China.With covert U.S. support, Malaysia will push for the deliberations by the continental shelf commission on its submission and press to speed up oil and gas development in the Nankang Ansha.

Regarding the COC consultations the United States, based on its strategic needs after its return to multilateralism, will set up new barriers to this China-let rules-making process for the South China Sea or create troubles via its proxies in ASEAN to bring the process to a standstill.