Defence of homeland is the primary responsibility of the armed forces. However, the 9/11 attacks on the World Trade Center in the US has infused a new dimension to homeland defence— or, more appropriately, homeland security.

Defence, according to the Oxford English Dictionary, denotes military measures or resources for protecting a country. This has traditionally translated into protecting national borders from external aggression and the connotation now includes pre-emptive attack against a would-be aggressor. Defence of homeland is the primary responsibility of the armed forces. However, the 9/11 attacks on the World Trade Center in the US has infused a new dimension to homeland defence—or, more appropriately, homeland security. The attack against the Indian Parliament on December 13, 2001 and Delhi’s willingness to go to war against the perpetrating country reinforced the convergence between defence and security when it comes to protecting national interests.

A large country with an area of 3.3 million sq km, India’s coastline stretches for over 7,600 km and a land border of 14,000 km, the alignment of some of which is under dispute. India has common borders with Pakistan, China, Bangladesh, Nepal, Bhutan and Myanmar. The pre-1947 state of Jammu and Kashmir had a 110-km border with Afghanistan also. The island territories of Andaman and Nicobar and Lakshadweep are also integral to the Indian Union. This vast entity has to be defended against attack which, for ease of understanding, can be classified as conventional, non-conventional and unconventional. Conventional attacks are those that are launched across land borders, coastlines or through the medium of air into the home territory, territorial waters or sovereign airspace. Nonconventional attacks include nuclear, biological and chemical attacks, as also attack from space. Considering the lack of experience in this particular type of attack, India’s defence strategy would have to be based on options derived from wargaming or scenario painting. Unconventional attacks are those mounted by non-state actors, like terrorists, from outside or within the country, with the intention of spreading terror. This category could also include cyber warfare, where technology is employed to target infrastructure like power grids, transportation systems or communication networks. Any treatise on homeland security warrants an in-depth analysis of each of these three types of attacks.