It is now more than 20 years since China enacted its proactive policy in the South China Sea (SCS). The core element of this policy remains the enforcement of Beijing's claims to most of the sea, and the outcrops within it. China has built sensor and weapon-equipped facilities on at least seven of the outcrops, and sends warships, or paramilitary vessels, to challenge non-Chinese vessels which sail close to them.
Analysts have a range of views on China's motives in seeking to control access to, and activity within, the SCS. Explanations which are often advanced include Beijing's desire to establish long term protection of its maritime lines of communication; Chinese intent to re-establish ancient tributary relationships with nations contiguous to the SCS; and, a strategy for Beijing to eventually introduce some form of "tithing" of transiting commercial shipping.
A recent theory, however, which is attracting increasing numbers of adherents, is that China's desire to control the SCS is predicated mainly by the country's need to position its Jin-class nuclear powered, JL-2 intercontinental ballistic missile-armed, submarines (SSBN) within range of mainland USA, and to minimise the chances of the SSBNs being detected, and tracked, by Western naval forces.
The theorists note that the Yellow Sea is too shallow for effective submarine operations, that the use of the East China Sea is constrained by its proximity to the Korean Peninsular, Japan and Taiwan, as well as being subject to intense surveillance by US, Japanese and South Korean submarines, and long range maritime patrol aircraft.
The SCS, though, is larger, and generally deeper, and permanent and exclusive control of the sea would facilitate undetected passage by SSBNs from Hainan, to positions east of the Philippines, within missile range of mainland USA.
Beijing is now giving great emphasis to SSBN operations by its SSBN fleet. The fleet's base on Hainan Island has come under the direct control of the Military Commission in Beijing, while the Southern Theatre Command, within which the facility is located, is commanded by Vice Admiral Yuan Yubai, a very experienced submariner.
In 2016 the UN-affiliated Permanent Court of Arbitration ruled that China's historic claims to the SCS were invalid, and that the "islands" within the sea were actually just "rocks". Beijing simply ignored the ruling, and regional naval forces have since done little to oppose what many in the international community see as creeping Chinese hegemony in the sea.
International concern over Chinese activity in the SCS, though, has ratcheted up, and, reportedly in response to diplomatic pressure from Washington, a de facto coalition of nations has emerged, and is carrying out freedom of navigation operations (FONOPS) and other evolutions in the sea and its environs. Recent activity by navies of this united front has included:
USA
Since 2017, the US Navy has been executing FONOPS about every two months. These operations usually entail deploying at least one Arleigh Burke-class destroyer to pass within 12 nautical miles of Chinese-occupied "islands".
France
In 2018 the French sent an amphibious task group, with British troops and helicopters, and German military observers embarked, into the SCS. In April this year, the French frigate Vendemiare undertook a passage through the Taiwan Strait, a move which resulted in Beijing withdrawing an invitation to the French Navy to participate in the 2019 PLA Navy Fleet Review.
Japan
September 2018 saw the Japan Maritime Self Defence Force (JMSDF) flat-topped destroyer (helicopter) Kaga, and submarine Kurushio carry out joint evolutions in the sea. In May this year, the JMSDF'S other destroyer (helicopter), Izumo, led exercises in the SCS with warships from Australia, India and the Philippines.
Australia
May this year saw a Royal Australian Navy task group, led by the landing helicopter dock Canberra, execute a FONOPS passage.
Canada
In late June this year two Royal Canadian Navy vessels, namely the frigate Regina, and the fleet replenishment tanker Asterix jointly executed a passage through the Taiwan Strait.
UK
2018 saw the assault ship Albion carry out a FONOPS passage, while, this year, the British frigate Argyll and the US Navy destroyer McCampbell have conducted joint operations in the SCS, while the frigate Montrose has executed a FONOPS passage.
South Korea
In September 2018 the Republic of Korea Navy destroyer Munmu the Great executed a FONOPS passage.
Also, Germany recently announced that it was considering sending a warship to operate in the SCS.
The situation is inherently dangerous, as foreign warships operating in the SCS usually acquire a close tail of PLA Navy frigates and destroyers. In September 2018 the US destroyer Decatur, and a Chinese Luyang-class destroyer, narrowly avoided a collision.
Furthermore, there are ever-increasing numbers of large, metal-hulled China Maritime Militia "civilian" fishing vessels carrying out observation and harassment operations in the SCS. According to unconfirmed reports, it was one such vessel which rammed and sank a Philippine fishing boat, off Reed Bank, in the SCS, in early June this year.
Tensions in and around the SCS seem certain to remain high, and numbers of warships active in the region are are likely to increase. Further incidents are therefore likely.