This could pose a major threat to US naval forces in East Asia in the event of a crisis.
As Richard Fisher, Jr. writes at the International Assessment and Strategy Center (Hat tip: NOSI):
China's new ASBMs pose a strategic as well as a tactical challenge to U.S. forces in Asia. At present the U.S. does not have anti-missile capabilities to defend large U.S. ships against this threat, so vulnerable targets, most importantly aircraft carriers, will have to remain out of missile range in order to survive. This factor will further limit the effectiveness of their already range-challenged F/A-18E/F fighter bombers. U.S. Aegis cruisers and destroyers now being outfitted with new SM-3 interceptors with upgraded radar and processing capabilities may in the future be configured to deal with this threat, but if so, they may not be available for other missions, like protecting people. The fact is that no anti-missile system is going to come close to providing reliable defense. For China, ASBMs provide a means for saturating U.S. ships with missiles. While ASBMs are bearing down from above, their attack can be coordinated with waves of submarine, air and ship-launched anti-ship cruise missiles.Sam Roggeveen at The Interpreter recently noted that the US is waking up to the threat posed by a Chinese ASBM. Roggeveen notes that for the moment one saving grace is that it is difficult to find an aircraft carrier at sea. He also notes that the US is shifting its priorities to reflect the new threat.
But what Roggeveen doesn't address is the threat posed by the new ASBM to US naval assets berthed in Japanese ports, most notably US fleet activities Yokosuka, the future home of the USS George Washington and the headquarters of the US Seventh Fleet. It may be difficult to find an aircraft carrier and its escorts at sea, but it is considerably easier to find them in their home port, as the accompanying image from Google Maps shows. (That's the USS Kitty Hawk to the right side of the map.)
View Larger Map
Google Maps also tells me that Yokosuka is less than 1400 kilometers from Tonghua in China's Jilin province, home to some Chinese DF-21 launchers.
The question I have is whether the Chinese ASBM will render US naval forward deployments in Japan obsolete, in that homeporting an aircraft carrier in Yokosuka may leave it vulnerable to a crippling first strike before even leaving port. Are anti-ballistic missile deployments in Japan — both by the US military and the Japanese Self-Defense Forces — reliable enough to protect US forces while in Japanese ports?
If not, hadn't the US and Japan be having a serious discussion about the impact of China's ASBMs on the future of US forward deployments in Japan, and with them, the future of the US-Japan alliance? Should the US consider relocating more assets from Japan to Guam to put them out of the range of ASBMs?
This is all speculative given that next to nothing is known about the specifications of the new missile, but its impact is potentially drastic. It's certainly something to watch.