The accelerated deployment of the Terminal High Altitude Area Defence (Thaad) anti-missile system by the United States in South Korea is a harbinger of instability and tension in East Asia. It is a classic instance of a purportedly protective military measure contrarily escalating regional fears and triggering dangerous tit-for-tat moves that leave all parties worse off.
By their very nature, missiles and their counters have enormous strategic capabilities to alter the balance of power and engender arms races. As witnessed during the Cold War, countries which develop missiles or anti-missile systems argue that their intention is purely defensive, but countries which fall within their striking range raise the alarm at the offensive impact of the former's manoeuvres. One side's safety becomes another's vulnerability. The ensuing zero-sum game situation breeds war-like thoughts and actions.
Thaad, manufactured by Lockheed Martin, is a reiteration of this problem known as a "security dilemma". On paper, Thaad is an advanced interceptor to secure US ally South Korea against the belligerence of North Korea, which has been testing progressively more powerful nuclear weapons and longer-range missiles.
The simultaneous launch of four ballistic missiles by Pyongyang on March 6 into the Sea of Japan/East Sea has speeded up the arrival of Thaad components at Osan Air Base, south of Seoul. The early advent is meant as a deterrent message from Washington to North Korean dictator Kim Jong Un that he cannot keep on intimidating the South without incurring a cost.
But North Korea's patron, China, views Thaad as aimed not at Mr Kim, but instead at weakening Beijing's relatively big nuclear missile arsenal. The monitoring, surveillance and early tracking technology embedded in Thaad could hinder China's freedom to launch a retaliatory "second strike" following a hypothetical first hit by the US or its allies. Together with the AN/TPY-2 radars already in position in Japan, Thaad is seen by Beijing as an American containment of expanding Chinese military muscle.
Chinese reactions to the fast-forwarding of Thaad's arrival in South Korea have been fierily nationalistic. A retired Chinese general has gone to the extent of urging Beijing to "conduct a surgical hard-kill operation that would destroy the target, paralysing it", that is, a pre-emptive attack on Thaad on South Korean soil before it becomes fully functional.
The Chinese government has instigated rare public protests and boycotts against South Korean companies doing business in China, reminiscent of the anti-Japanese demonstrations witnessed in 2012 in China over the Senkaku/Diaoyu island territorial dispute. Beijing is not just leveraging its economic advantage as the chief buyer of South Korean products and services, but also issuing dire warnings that Thaad will be countered with a fitting military rejoinder.
The Rocket Force of the People's Liberation Army is said to have started building next-generation "hypersonic missiles" to pierce Thaad's defences. If these new weapons come into play, Japan would be compelled to respond in kind to restore a balance of firepower. And South Korea will suffer the most as the staging ground for an unrelenting war of wills between the US and China.
Since the recent ouster of the scandal-plagued, pro-American conservative president Park Geun Hye, the future of Thaad has come under a cloud. The upcoming South Korean elections are expected to hand over the Blue House in Seoul to the liberal Moon Jae In, who is wary of Thaad and an advocate of avoiding the spectre of South Korea becoming a victim to intensified US-China military competition. China will surely be egging on Mr Moon's impending victory to try and politically defeat Thaad.
However, no matter who wins the South Korean presidency in May, one aspect of China's anti-Thaad campaign remains completely unpredictable. Mr Kim is looking less and less amenable to Beijing's stick and carrot. If he keeps ignoring China's advice and launches further missiles and nukes as part of his domestic political consolidation agenda, not even a liberal South Korean administration will have the political capital to call off Thaad.
When Beijing temporarily halted imports of North Korean coal late last month, Pyongyang's media mouthpiece openly ridiculed China in an unprecedented public outburst as "dancing to the US tune". Rising mistrust between Beijing and Pyongyang implies that China lacks the sway to moderate North Korean bellicosity, which in turn would justify Thaad to a majority of South Koreans.
How can all concerned parties break out of this vicious circle of hostility and mutually reinforcing insecurity? The best way out is for the two principal rivals, China and the US, to reach an overall political accommodation to back off from brinkmanship. But the Trump administration's negative perception of China on multiple issues suggests this is wishful thinking.
Unlike the worsening China-America tussle, the bonhomie between US President Donald Trump and Russian President Vladimir Putin does hold out hope for resolving a similar security dilemma over the US' sea-based Aegis ballistic missile defence system, which Russia alleges to be an American instrument to endanger its security. In return, the US is blaming Russia for reneging on the Intermediate-Range Nuclear Forces Treaty by secretly testing prohibited cruise missiles. The stakes in this case are as high as the heated contest over Thaad. But the prospects of a settlement are comparatively better because of the political openness between Mr Trump and Mr Putin.
After all, missiles and shields are military tools for achieving political ends. Unless China and the US reach a modicum of political tolerance towards each other, lesser remedies like direct talks between the US and North Korea or a revival of the "sunshine policy" between South and North Korea have little chance of extricating East Asia from the missile morass.
•The writer is a professor and dean at the Jindal School of International Affairs in Sonipat, India. His latest book is Modi Doctrine: The Foreign Policy Of India's Prime Minister.