People at a railroad station in Seoul watch a news report on Wednesday after the Democratic People's Republic of Korea announced that it had conducted its first hydrogen bomb test. JUNG YEON-JE/AFP

Republic of Korea President Park Geun-hye announced recently that her government will consider the deployment of the Terminal High Altitude Area Defense system, an advanced US anti-ballistic missile defense system, in the ROK.

Park's comment came after the Democratic People's Republic of Korea early this month carried out its fourth nuclear test since 2006, giving rise to speculation about the THAAD missile defense system's deployment, which has the potential to readjust the regional strategic structure and trigger an arms race in East Asia.

Unlike the ROK's previous ambiguous "Three Nos" policy - No Request, No Consultation, No Decision - Seoul's more favorable stance toward the US defense system is becoming clear, so too is Washington's strategic ambition.

The THAAD system, if deployed in the ROK, will obviously have a negative impact on regional security. Chinese Foreign Ministry spokesman Hong Lei has reiterated Beijing's stance that a country should consider other countries' safety and interests as well as the peace and stability of the whole region when seeking its own safety.

Strategically, the possible deployment of the THAAD system in the ROK would further worsen the peninsula situation, fueling the arms race between the ROK and the DPRK and leaving less room for China's neighborhood policy.

As Japan also showed interest in introducing the THAAD system last month, the ROK, and Japan could witness substantial progress in their military alliance with the US, which might even incubate a sort of "Asian NATO", if both Tokyo and Seoul decided to deploy the US system on their soil.