Here is what the US had to day about BMD as recently as 2014:
But as a general proposition,
the existing homeland defense posture is effective against small numbers of early generation intercontinental-range ballistic missiles.
Early generation missiles are relatively unsophisticated technically, meaning that they take longer to ready to launch, are slower in flight, lack missile defense countermeasures and, if not the result of a rigorous development and
testing program, may lack reliability. An early generation force, as opposed to an early generation missile, is also likely to be relatively small in number.
Later generation missiles fly sooner, faster, further, and more reliably, may have missile defense countermeasures along with multiple warheads, and are likely to exist in numbers sufficient to enable the kind of salvo launches that can overwhelm either sensors or interceptors or both.
The short-comings of available BMD systems in dealing with countermeasures and large raid sizes are well known.
Accordingly, the Obama administration set out as national policy commitment to:
(1) maintain an advantageous defensive posture of the homeland against limited strikes by countries like North Korea and Iran and
(2) field phased, adaptive regional defenses in partnership with U.S. allies in each region where it offers security guarantees.
Hence they can be deployed and effective against early generation threats from countries like North Korea but cannot be effective against the large and mature forces of Russia and China.
This analysis is the basis of the American assessment that
BMD technical options are available that promise stabilizing as opposed to destabilizing benefits.
http://www.ifri.org/sites/default/files/atoms/files/pp50roberts.pdf
29 November 2012
India: How Credible is its Ballistic Missile Defence?
The lack of systematic policy considerations guiding the Ballistic Missile programme has seen the DRDO act quite hawkish on the score of achieving the capability. But given that this system threatens Pakistan’s first strike capability, it is bound to lead to uncertainty and insecurity on that side of the border. The Indian BMD will thus serve to only accentuate the current missile race in South Asia.
Domestically too, statements
assuring BMD capabilities to just two cities will prove to be a major headache to the central government, as selective defence of cities is bound to be contested by other parts of the country, thus possibly arousing domestic turmoil. It seems that missile testing and potentially destabilising hawkish behavior on ballistic missile defence in India has acquired a certain bureaucratic momentum of its own. It is thus important for the government to reign in these programmes. While not compromising on the technological development of Indian defences, the government needs to ensure that these capabilities do not foster insecurity in the region.
http://www.ipcs.org/article/india/india-how-credible-is-its-ballistic-missile-defence-3768.html
It seems to be a very restricted BMD.. How many major cities are in India..
If Pakistan gets its own BMD it will be far more protected than India, due to geography alone..