The strongest of bilateral relations are anchored in defence and security cooperation. Economic relations are indeed important. But they are not a full measure of the depth of a partnership. The Britain-US relation is the best example, with bilateral trade only 2.7% of the total US trade, only 1% higher than the India-US figure.There are many reasons why defence and security cooperation could begin driving wider Indo-US bilateral ties. The most important factor is that both nations are deeply suspicious of the ‘peaceful rise’ of China. Despite being militarily inferior, China harasses American ships and planes in the South China Sea. Further, China’s ‘nine-dashed line’ demarcation policy in the South China Sea that runs counter to the UN Convention on the Law of the Sea ( UNCLOS ), and its aggressive posturing against Vietnam and Japan over disputed islands, are portentous.The joint statements issued during Prime Minster Narendra Modi’s trip to the US last September and during President Barack Obama ’s January visit to India have left no doubt regarding the consternation of both nations at the Chinese policy.This found further expression in the US-India Joint Strategic Vision for the Asia-Pacific and Indian Ocean Region. References to “rising tensions”, the need to ensure “freedom of navigation and over flight… especially in the South China Sea”, and the need to settle disputes according the UNCLOS in the above documents have underscored the interests of both nations in checking China.There are also two adjuncts to the above. One is that the most dramatic part of the Obama administration’s ‘pivot to Asia’ or ‘rebalancing’ strategy is to counter China militarily. The other is that Asia needs a balance to China. At a time when US appetite for intervention has ebbed, India can assume this role effectively. But it will require taking Indo-US defence cooperation to a new level.This cannot merely happen by the US selling select defenceware to India. Nor will the US becoming India’s largest defence supplier with purchases totalling over $10 billion – and replacing its reliable arms source, Russia – alone suffice. India and the US renewed the Defence Framework Agreement signed in 2005 for another 10 years.The Defence Trade and Technology Initiative (DTTI) was also launched with four ‘pathfinder projects’, one of which is biological warfare-protection gear for soldiers. Although they are important in themselves, tinkering at the edges cannot substantively enhance India’s defence capabilities. For a meaningful change, India and the US should build a cooperative defence architecture similar to the ones the US has with Britain and Japan.A slew of bilateral treaties and agreements – prominently, the US-UK Agreement for Cooperation on the Uses of Atomic Energy for Mutual Defence Purposes (1958) – paved the way for closer defence cooperation between the US and Britain. Japan, too, benefited from US defence technology transfer and co-production agreements. The cooperation led to the co-production of several sophisticated platforms such as P-3C maritime patrol and F-15 aircraft. Over time, it developed Japan’s ‘modern aircraft manufacturing capability’.India and the US could conclude similar agreements. First, such arrangements will dispense the need to confine co-production to ‘pathfinders’.Second, they could facilitate transfer of critical technology to fill gaps in India’s defence production capabilities and set the stage for coproduction of large platforms. Such arrangements could further strengthen India’s highly professional armed forces to enable India to become, in Obama’s words, “even closer partners” in ensuring “mutual security”.The reach of the Indian Navy needs to be expanded. The US could assist India’s nuclear submarinebuilding programme just as it had done for Britain in the 1950s, helping the latter in its launch of HMS Dreadnought, Britain’s first nuclear submarine, in 1960. Extending assistance to build nuclear aircraft carriers could give the Indian Navy strategic depth. Obstacles such as nuclear non-proliferation issues may not be insurmountable after the Indio-US nuclear agreement. Similarly, large projects can be identified for the Indian Air Force and Army for technology-transfer, co-production etc.The US also stands to benefit. First, it could take advantage of cheap production in India and outsource many of its requirements from India. Second, co-production would also ensure better economies of scale. These could also make defence exports competitive for the US. Third, India’s defence requirements are expected to grow significantly that the US could tap.Fourth, some of the needs of India are immediate and the US could benefit from off-the-shelf sales. Fifth, a liberal US policy could give it more opportunities to increase its share from the present 40% of India’s total capital expenditure on arms imports.India, in many ways, is better placed than Japan or Britain after World War II to partner the US in safeguarding global security. But India’s role can be effective only if Washington takes the defence cooperation to a higher level.The writer is Additional Secretary to the President of India