在中美所有關係當中，軍事關係是最困難的。二十多年來，兩個大國在其他領域的關係起起伏伏，而防務關係的模式卻局限在“開和關”上。缺乏理解和根深蒂固的懷疑使兩軍關係始終處在低水平，且異常脆弱。不過近年出現了積極動向，值雙邊關係總體下滑之際，一些觀察家甚至稱讚兩軍關係是亮點。看來，中美軍事關係已經進入一個“新常態”，它取得的進展令人鼓舞，同時挑戰也相當嚴峻。

衡水巡防艦隨一艘阿利·伯克級驅逐艦和一艘高郵湖補給艦駛往夏威夷參加2016 RIMPAC環太平洋軍演。

這個“新常態”下的一個積極進展是近來兩軍關係出現彈性。雙方的諒解就是，兩軍關係如此重要，即使困難當頭，也必須保持。而今，中國人民解放軍和美軍的互動頻率與密度加大。中國海軍參加美國太平洋艦隊主導的“2016環太平洋軍事演習”，以及海軍作戰部長約翰·理查森上將、太平洋艦隊司令斯科特·斯威夫特上將、陸軍參謀長馬克·米雷將軍相繼訪華，就是兩國因南海和“薩德”部署互斥之際仍保持溝通與交流暢通的實例。高層訪問不僅次數頻繁，也開誠布公、暢所欲言。

“新常態”的特點還在於機制性交流與對話的擴大與深化。兩軍每年舉行的“國防部防務磋商”和“國防部工作會晤”更具互動性、建設性，而雙方旨在避免海空意外相遇的“海上軍事安全磋商”機制已經取得具體成果。在國家層面，兩國國防官員都參加了“戰略安全對話”。兩軍還致力於在戰略規劃部門、不同軍種等對口防務領域之間建立新的對話平台。

功能性交流構成兩國軍事關係的實質，其中包括軍事院校的互訪、學術交流——比如中國軍事科學院和美國陸軍戰爭學院聯合主辦國際問題研討會、軍事醫療單位和反恐機構間的交流、美國二戰期間失蹤人員遺骸定位備案合作、艦船互訪等。近年雙方的聯合演習也多於以往，如在亞丁灣舉行的打擊海盜聯合演習、在中國和美國舉行的人道主義救援減災演習，艦船到訪期間舉行的搜救演習。功能性交流是建立信任和培養合作習慣的重要途徑，兩軍每年開展的交流項目已超過50個。

2014中美海軍艦艇在亞丁灣舉行聯合反海盜演練（選自：新華網）

“新常態”中另一個值得注意的新發展，是兩軍之間有關預防管理危機的措施與機制。2014年底，中美兩國國防部達成兩個諒解備忘錄，一個是關於重大軍事行動通報，另一個是關於海空相遇安全行為準則。去年晚些時候，兩個諒解備忘錄又加進了“使用國防部直通電話的軍事危機通報機制”附件，以及相遇準則中有關空中相遇的部分。如今，危機預防管理和增進互信措施是兩軍關係中重要的新要素，雙方越來越頻繁地與對方相遇，而即使在最壞情況下，它們也是至關重要的穩定器。

況且，中美軍事關係已超越傳統兩國邊界，走向地區乃至全球領域。隨着中國軍事影響力擴大到全球，它發現自己有更多機會與美國對手合作。譬如，在東盟防長擴大會議框架下舉行的人道主義救援減災、軍事醫學、搜救、反恐等聯合演習中，中美軍隊都發揮了主要的支援作用。中美海軍巡邏艦每年在亞丁灣進行聯合演練。中國海軍艦艇與俄羅斯、美國、挪威軍艦共同執行了聯合國銷毀敘利亞化學武器的任務。儘管多邊框架下的軍事合作仍在起步階段，但它預示着一個“新常態”，即中美兩軍將有更多共同利益，並將承擔更多共同責任。

然而，這個“新常態”也有消極一面。中國與鄰國（其中一些是美國盟友）的雙邊糾紛給兩軍帶來新的摩擦，引發了嚴重多邊和地區後果。對中國來說，領土主權是最重要的國家利益。而對美國來說，對盟友的防務承諾是其地區安全架構的關鍵。當前美國的軍事動向，包括在西太平洋部署最先進武器裝備、增加未來的軍事存在、舉行盟國間大規模軍演、在南海實施“航行自由行動”、實施新的防務安排如在菲律賓輪流部署軍事基地、升級與日本的安保條約、向中國的鄰國出售武器、決定在韓國部署“薩德”系統等，所有這些，都讓中國感到美國是在利用其同盟框架抑制中國的尤其是軍事上的崛起。這已經被證明是繼續增進兩國軍事關係的一個主要障礙。

歸根到底，當前中美防務關係比以往更有彈性，更具實質性，也更加廣泛。但要讓它始終行駛在積極的軌道上，仍有大量工作要做。

Of all relationships between China and the United States, the military one had been the most difficult. For more than two decades, while relations between the two great powers in other fields had gone through ups and downs, defense relations have been trapped in an on-and-off pattern. Lack of understanding and deep-rooted suspicion had kept military ties at a low level and rendered them highly vulnerable. However, recent years have witnessed more positive developments, and some observers have even cheered the military relation as a highlight in a generally downhill bilateral relationship. It seems that the China-US military relationship has entered a state of “new normal”, in which progress is encouraging, though challenges are daunting.

The Hengshui frigates sails behind an Arleigh Burke class destroyer and the Gaoyouhu supply ship, all on their way to Hawaii in the RIMPAC 2016 Exercise.

One positive development in this “new normal” pattern is the newly found resilience in the mil-mil relation. The mutual understanding is that military ties are so important that they have to be maintained even in difficult times. The Chinese PLA and the US military are now interacting with each other with more frequency and greater density. The Chinese navy's participation in the RIMPAC 2016 Exercise hosted by US Pacific Fleet, and the consecutive visits to China by Adm. John Richardson, Chief of Naval Operations, Adm. Scott Swift, Pacific Fleet Commander, and Gen. Mark A. Milley, Chief of the Army Staff, are examples of unimpeded communication and exchanges at times when the two countries are pointing fingers at each other in the South China Sea and on the THAAD deployment decision. High-level visits have not only been frequent in number but also candid and communicative in style.

The “New Normal” also features the extension and deepening of institutionalized exchanges and dialogues. Annual Defense Consultative Talks (DCT) and Defense Policy Coordination Talks (DPCT) between the two military establishments have been carried on in a more interactive and constructive way. The mechanism of the Maritime Management Consultation Agreement (MMCA), in which both sides have tried to work out ways to avoid accidents at sea and in the air, has yielded concrete results. At the national level, defense officials on both sides have participated in the Strategic and Security Dialogue. And the two militaries have worked to set up new dialogue platforms between defense counterparts, such as between the strategic planning organizations and the services.

Functional exchanges make up the substance of the military relations, including reciprocal visits by military academies and schools, academic exchanges such as a seminar on international issues jointly sponsored by the Chinese Academy of Military Science and the US Army War College, the exchange between military medical units, counter-terrorism units, cooperation of archivists to locate the remains of US MIAs during the Second World War, and port calls. Recent years have seen more joint exercises than ever before, such as a counter-piracy joint exercise in the Gulf of Aden, HADR (humanitarian assistance and disaster relief) exercises in both China and the US, and SAR (search and rescue) exercises in conjunction with port visits. Functional exchanges are the essential way to build trust and develop the habit of cooperation. The two militaries carry out more than 50 exchange programs every year.

Chinese and American navy vessels were on joint Anti-piracy Drill in the Gulf of Aden in 2014（Source:Xinhuanet)

Another new development worth noting in this “New Normal” are the measures and mechanisms to prevent and manage crisis between the two militaries. At the end of 2014, the US Department of Defense and Chinese Ministry of National Defense agreed upon two MOUs (Memorandum of Understanding), one on notification of major military activities, another on rules of behavior for safety in air and maritime encounters. Later last year, an annex of “military crisis notification mechanism for use of the defense telephone link” and an air-to-air part of the rules of encounters have been added to the two MOUs. Crisis-prevention management and confidence building measures are important new elements in the relation now that both militaries find themselves come across each other frequently. They are crucial stabilizers even in the worst circumstances.

In addition, the China-US military relationship goes beyond its traditional bilateral boundary, and moves into regional and even global arenas. With the Chinese military extending its global reach, it finds more occasions to cooperate with its US counterpart. For example, both militaries take a major supporting role in the ADMM+ framework joint exercises on HADR, MM, SAR, counter-terror, and so on. Chinese and American naval patrolling ships carry out joint drills each year in the Gulf of Aden. The Chinese naval vessels, together with Russian, American and Norwegian vessels, have jointly accomplished the UN mission to destroy chemical weapons from Syria. Even though military cooperation in a multilateral framework is still nascent, it foreshadows a “New Normal” where the two militaries may have more common interests and share more common responsibilities.

However, the “New Normal” pattern has a negative side too. China's bilateral disputes with its neighbors, some of whom are US allies, have brought the two militaries to new frictions, triggering significant multilateral and regional ramifications. For China, territory is the vital national interest, and for the US, the credibility of its defense commitment to allies is key to its regional security architecture. The current US military development, including deployment of the most advanced weaponry to the Westerm Pacific, increase of forward military presence, large-scale allied exercises, FONOPs in the South China Sea, new defense arrangements such as the rotational deployment to the military bases in the Philippines, upgrading of the security treaty with Japan, arms sales to China's neighbors, and the decision to deploy a THAAD system in the ROK, all give China the impression that the US is using its alliance framework to suppress China's rise, especially in the military dimension. This has proven to be a major obstacle to further improvement of the military relation.

To sum up, the current China-US defense relationship is more resilient, substantive, and extensive than before. However, to keep it on a positive track, there is much to be done.