This article is part of the World Economic Forum's Geostrategy platform

Hosted by the US Navy’s Pacific Fleet and due to get under way on 27 June, this year's Rim of the Pacific (RIMPAC), exercise is notable, so far, for the fact that the US has disinvited the People’s Liberation Army Navy (PLAN).

Routinely dubbed ‘the world’s largest international maritime exercise’, RIMPAC 2018 will be the 26th in the series of biennial naval manoeuvres. In broad terms, this year’s event is on a par with two years ago – 26 participating nations, 47 surface ships, five submarines, more than 200 aircraft and 25,000 personnel. But a look behind the numbers reveals real differences.

China disinvited

The removal of the PLAN from the list of official invitees is the most striking.

According to the Pentagon, the move was ‘an initial response’ to China’s continued militarization of the South China Sea – a charge, of course, that Beijing rejects. The PLAN was first invited to RIMPAC 2014. It was invited again (and attended) in 2016, despite the tensions then over the South China Sea. The about-turn by Washington this time is telling.

Officially, the Pentagon said China’s actions – including recently landing bomber aircraft on Woody Island – only served to raise tensions and destabilize the region. The US move perhaps also reflected the realization in the Pentagon of the advances China has made in just the last two years in developing the military potential of the contested features it has been working on. Russia participated once in 2012, was invited again in 2014, but declined as relations deteriorated over Crimea, and has not been invited since.

On the other hand, there are a number of newcomers to RIMPAC this year – Brazil, Israel, Sri Lanka (which is interesting, given the diplomatic and economic inroads Beijing has been making there) and, perhaps most significantly, Vietnam.

The US–Vietnam military relationship has shifted markedly in recent years, as Washington now views Vietnam as a potentially significant counterweight to China. In early March 2018, the USS Carl Vinson became the first US aircraft carrier to visit Vietnam since the end of the war there in 1975.

Image: IISS

Overall, international participation in RIMPAC has grown significantly during this decade, from just 14 nations in 2010. Washington may be heartened by the fact that numbers have held up this year. But it probably is not complacent, given the obvious concerns over what appear, to the region, to be mixed messages from the Trump administration on Indo-Pacific alliances and commitments.

Despite strong statements at this year’s IISS Shangri-La Dialogue from France and the United Kingdom on maritime commitments to the region, the trend of growing European participation in RIMPAC appears to have stalled for now. From two (France and the Netherlands) in 2010, it rose to seven in 2016, but has fallen back to four this year.

Hard and soft power

Centred chiefly in and around the Hawaiian Islands, RIMPAC has always seemed to be more about fostering maritime diplomacy and partnership than honing hard-power capabilities. It has also been about underlining the US role as the chief custodian of maritime influence in the region. But there has still been an element of assisting in regional capability development, and some serious high-seas manoeuvres and weapons tests.

Of greater note in this year’s iteration are the clear signals of how the US, spurred by the challenge from China, is seeking to regenerate neglected anti-ship capabilities. Among this year’s RIMPAC debuts should be a live-firing of a US air-launched long-range anti-ship missile and the launch of a land-based version of the naval strike missile (NSM). The US Navy has just selected the NSM to fill the over-the-horizon anti-ship requirement for its littoral combat ship fleet and future frigates.

Finally, a potent and now customary image from all recent RIMPACs has been the aerial view of the assembled naval power in multiple lines at the end of the exercise – symbolizing Asia’s naval rise, but also emphasizing US preponderance and tutelage.

The PLAN will be absent this time. But it has just put on its own most potent naval display to date, with images of neat lines of naval vessels not unlike the RIMPAC formation – 48 warships and submarines and 10,000 personnel according to Beijing.

Of course, there are still caveats over the real capability behind the Chinese images, but again signs of significant change were there to see. It was another pointer to how the strategic context in which this year’s RIMPAC will be taking place is different. And, while the PLAN may not be an invited guest, it will surely be keeping a close eye on proceedings.