Since the end of WWII, America's naval might has been undisputed and our aircraft carriers have been its crown jewels. However, the days of dominance could end with China's new DF-21D ballistic missile—the only device on Earth capable of sinking an aircraft carrier—four and a half acres of sovereign US territory—with one shot.

The DF-21D (Dong-Feng 21 variant D) is the world's first and only anti-ship ballistic missile (ASBM). It's a two stage, land-launched missile with a maximum estimated range of 2,700 to 3,000 km. Its single fuel-air explosive warhead packs 200 to 500 kilotons. It was developed by China Changfeng Mechanics and Electronics Technology Academy as part of the country's massive military modernization effort, an initiative focused primarily on developing overwhelming missile technologies for which there are no effective defenses. The Defense Department believes it entered active service around 2009.

While the Chinese obviously aren't saying much on the inner workings of the new missile system, military experts believe it will rely on China's Over the Horizon radar (OTH) to monitor a 3,000-km swath of the South China Sea, where China is now claiming dominion over. The OTH system bounces its radar signal off the ionosphere to see past the curvature of the earth. If the OTH detects a carrier battle fleet, the system instigates a set of Yaogan satellites to search the area and provide precise targeting data. Additionally, when the OTH detects an approaching fleet, the system will reportedly launch a swarm of micro-satellites into low orbit where they will help refine the targeting data further and transmit it back to the onshore command center. Meanwhile, UAVs will be launched to track the fleet. Once the missile has been launched and separated from its first stage, the warhead employs synthetic aperture radar to find the carrier. It receives real time telemetry data as it locks onto its target and initiates its terminal descent.

This capability could be used to effectively deny US carriers from intervening in, say, the Taiwan Strait. It could also be used as a very large stick in resolving local territorial disputes. Many members of the security community also worry that the FAE warheads could easily be replaced with nuclear ones. If that occurred, it would very lead to an arms race with Japan and India (neither of whom are particularly fond of the Communist PRC). Or, it could dissolve the US-Russian INF Treaty, which prevents the two countries from from deploying short and intermediate range land-based ballistic and cruise missiles. [Strategy Page - Wired - Dept of Defense - SinoDefense - Weapon and Technology - Wikipedia]