Both India and Japan have evinced interest in deploying defences against ballistic missiles because of the threat they pose. Significantly, both have shifted their stance on US Ballistic Missile Defence (BMD), from previous opposition to active support. Notwithstanding certain basic differences between India and Japan on the nature and degree of interest and participation at present, shared interests offer an opportunity for them to cooperate with each other on the BMD issue to further consolidate the 'strategic partnership' understanding they have evolved.

The demand for an infallible missile and homeland defence against anticipatory threats from adversarial state actors as well as amorphous non-state actors has become accentuated in the US in the post-9/11 era. In consonance, the importance of anti-missile defence shield has grown in primacy and has witnessed a changing orientation to an amalgamation of an integrated Layered Defence System. However, the two main question on the development of such a system are whether it will reach a meaningful completion and whether such a system will be cost-effectived.