The Chinese government announced January 11 that a ground-based midrange anti-ballistic missile (ABM) had been successfully tested earlier that day.
Ten years ago, China vehemently opposed the development of the US Theatre Missile Defense system (TMD) and National Missile Defense System (NMD). When its protests proved fruitless China started to develop its own ballistic missile defence system.
From some points of view, it was not necessary to oppose US development of an ABM system since after all ABMs are defensive technology. The U.S. faces the threat of ballistic missile attack and felt the need to develop its own defense system, and the threat, from the US point of view, may include China's missile attack and counter attack capabilities. China has never intended to become a threat to the U.S., and in developing its own limited missile warfare capabilities, China's intentions are purely defensive. However, China's limited defensive power may still be regarded by the U.S. as a threat.
By the same token, US security concerns are regarded by China as a threat. And China thinks it has the right to live free of threats to its security. Therefore, when the U.S. threatened to launch a nuclear war against China in the 1950's, China was obliged to develop its own nuclear weapons. (This is also the logic behind North Korea's nuclear weapons ambitions.) Furthermore, as long as the U.S. retains its nuclear forces and periodically poses a threat to China (both the Chinese mainland and Taiwan) through its weapons sales to Taiwan, the Chinese government will maintain its nuclear deterrent. (This is also why North Korea will not abandon its nuclear weapons development.)
That the U.S. possesses nuclear weapons is a matter of its own sovereignty, but once the U.S. interferes in other countries' internal affairs, it infringes on their sovereignty. Currently, the US ABM defense capability allows it to interfere in world affairs without having to worry about retaliation from the rest of the world. So, when this seemingly reasonable missile defence system is married with the aggressive foreign policy of the U.S., the issue of missile defense takes on a new complexity – missile defence systems can enhance a country's security by fending off missile attacks from enemy countries, but at the same time, can make those who possess them bold enough to launch aggressive and proactive foreign policies.
In short, opposition to missile defense systems is never going to be the mainstream. Missile defence systems raise a country's defense abilities and the need for them is shared by all the countries. The best approach is to develop one's own rather than oppose those of other countries. Those who oppose missile defense may well find themselves under threat of missile attack. Security cooperation treaties can help build a safer international environment, but it is difficult to ensure an aggressor will not appear, or to guarantee a missile attack will never occur. Facing such scenarios, a sovereign state still needs a high-credibility deterrent to minimize threats and, should a missile attack occur, anti-missile systems to defend against it.