In 1927, when Mahatma Gandhi was on a visit to Ceylon (as Sri Lanka was known then) he said that given the commonalities between India and Ceylon, there was no reason why they should quarrel. Jawaharlal Nehru, who was drawn to Buddhism, saw it as the basis of strong bonding between the two peoples. And yet, from the time of Gandhi and Nehru, till date, a variety of issues had kept cropping up regularly, bedevilling ties.

Prior to the Independence of India and Ceylon, in 1947 and 1948 respectively, the divisive issue was the presence of a million people of Indian origin in the island, mostly working in the plantations. While Ceylonese nationalists demanded that they be repatriated to India, Indian nationalists resisted it. Not surprisingly, Independent Ceylon's first major act was to disenfranchise and deny the Indians citizenship.

While divisive issues varied from time to time, the underlying factor in the adversarial relationship has been a difference in strategic vision. India has consistently believed that Sri Lanka is vital for its security in the Indian Ocean Region (IOR), and that the island must be within its political and defence perimeter.

In contrast, Sri Lanka has consistently laboured under fear of Indian domination or even absorption, due to the asymmetry in power, physical proximity, historical links, and ethnic and religious commonalities. While India has attempted to block the influence of powers thought to be inimical to it, Sri Lanka has cultivated India's rivals to use them as a check on India.

According to Punsara Amarasinghe, author of a paper titled "Small State Dilemma" (Open Military Studies 2020), a Sri Lankan leader had warned before Independence, that "the day Ceylon (Sri Lanka) dispensed with Englishmen completely, the island would go under India." Lankans were also disconcerted by Indian scholar-diplomat K.M Panikkar's 1945 thesis that cooperation between India, Burma and Sri Lanka would be "a pre-requisite for a realistic policy of Indian defence." He wrote: "The first and primary consideration is that both Burma and Ceylon must form with India a basic federation for mutual defence whether they will it or not. It is necessary for their own security."

In response, one of the first things that free Sri Lanka did was to sign a Defense Pact with the UK giving it air and naval bases. This increased India's anxieties. Amarasinghe quotes Indian Navy officer Ravi Kaul's 1974 article that said: "Sri Lanka is as important strategically to India as Eire is to the United Kingdom or Taiwan to China. As long as Sri Lanka is friendly or neutral, India has nothing to worry about, but if there be any danger of this island falling under the domination of a power hostile to India, India cannot tolerate such a situation endangering her territorial integrity."

More recently, retired Indian National Security Advisor, Shivshankar Menon, had written that Sri Lanka's strategic importance lay in its location at India's doorstep. He described it as a "permanently-stationed aircraft carrier" off the South Indian coast.

In 1963, Lankan Prime Minister Sirimavo Bandaranaike, raised the hackles in India when she signed a Maritime Agreement with China. This was a year after China invaded India. India feared that the Sino-Lankan agreement could acquire a military dimension at a time when India's Navy was still a Cinderella. In 1962-63 India expected Sirimavo to support India in its territorial dispute and war with China, but that was not forthcoming. Her only effort was to make the adversaries negotiate a settlement.

In April 1971, when Sirimavo faced an attempt by the Janatha Vimukthi Peramuna (JVP) to seize power, India sent choppers to help the Lankan forces. But in December 1971, when India needed her support for the liberation war in Bangladesh, Sirimavo gave refuelling facilities to Pakistan's military aircraft on grounds of being non-aligned. India was being rubbed on the wrong side.

After Sri Lanka liberalised its economy in 1977-78, President J.R. Jayewardene joined the Western camp, while India's relations with the US had soured because of the latter's support for Pakistan in the Bangladesh liberation war in 1971. After the 1983 anti-Tamil riots in Colombo, and the influx of Tamil refugees into Tamil Nadu, India began to back the Tamil cause and the militants too alienated Colombo.

There was also a larger security/geopolitical dimension to the Indian intervention as ex-Indian envoy in Colombo J.N.Dixit pointed out. "It would be relevant to analyse India's motivations and actions vis-à-vis Sri Lanka in the larger perspective of the international and regional strategic environment obtaining between 1980 and 1984,"wrote Dixit.

Amarasinghe quotes the then Minister of National Security, Lalith Athulathmudali, as saying: "India wanted to control her surroundings. They had an obsession that Trincomalee was being given as a base to the US."

In mid-1987, India stopped the advance of the Sri Lankan army against the Tamil Tiger militants in North Sri Lanka. India pressured Jayewardene to sign the India-Sri Lanka Accord in July 1987 and accept an Indian Peace Keeping Force (IPKF). The Accord also made Sri Lanka bar forces inimical to India from using its ports and other facilities.

To get even with India, President Premadasa armed the Tamil Tigers to help them fight the IPKF. Later, he gave the IPKF an ultimatum to leave. A miffed India refused to give military aid to Colombo when it resumed fighting with the Tigers in the 1990s.

However, in the final stages of the war in 2007-2009, India and Sri Lanka tied up to defeat the Tamil Tigers who had become a common enemy after the assassination of Rajiv Gandhi in 1991. A "troika" of top security officials from Delhi and a "troika" from Colombo, facilitated cooperation.

But there was a change for the worse post-2010, when China entered Sri Lanka as a big builder of infrastructure. The deep-water port project in Hambantota raised the hackles in New Delhi. In 2010, Alok Kumar and Ishwaraya Balakrishnan said in a paper in the Indian Journal of Political Science: "The construction of this port will bring China within breathing distance of India's southern coast where sensitive installations, including power plants, are present. It could also help China in keeping a track of India's nuclear, space and naval establishments in South India and also serving as a listening post". India's apprehensions increased when, in 2017, the port was leased to China for 99-years.

In 2014, a Chinese nuclear submarine "Changzheng 2 had docked in Colombo almost coinciding with the visit of President Xi Jinping. New Delhi saw this as Beijing's cocking a snook at New Delhi with Colombo's connivance. In Indian eyes, the docking violated the Indo-Sri Lanka Accord which stipulated that no port in Sri Lanka will be made available for military use by any country in a manner prejudicial to India's interests.

But China also has security interests in the Indian Ocean, points out Amarasinghe. Zhao Nanqui, the director of the General Logistics Department of the People's Liberation Army said, "we can no longer accept the Indian Ocean as an ocean only for the Indians". Zhang Ming, a Chinese naval analyst had warned that approximately 244 islands from India's Nicobar and the Andaman archipelago could be used by India as a chain to hinder Chinese ships entering the Strait of Malacca.

However, when Gotabaya Rajapaksa came to power in 2019, India-Lanka relations improved. Lankan Foreign Secretary Adm. Jayanath Colombage said: "We have to understand the importance of India in the region and we have to understand that Sri Lanka is very much in the maritime and the air security umbrellas of India. We need to benefit from that".

Since then, Indian and Sri Lankan navies have conducted joint exercises nine times under the SLINEX series. Recently, India and Sri Lanka agreed to set up a joint Maritime Rescue Coordination Center (MRCC) with a $ 6 million grant from India. Sri Lanka would also get a donation of a US$ 19.81 million worth 4,000-ton floating dock, a Dornier surveillance aircraft and a ship repair dock from India. Sri Lanka became part of India's Security and Growth for all in the Region (SAGAR) scheme. Cooperation in Maritime Domain Awareness (MDA) is part of SAGAR.

When Sri Lanka hit an unprecedented economic crisis in 2022, India pumped in US$ 3.8 billion to help Sri Lanka buy essentials like food, fuel and medicines. Indeed, India is the only country to help to this extent.

But experience shows that goodwill can come under strain for the slightest of reasons. Two recent incidents illustrate this. The grant of a US$ 500 MW renewable energy project to Indian investor Gautam Adani drew carping comments from opposition MPs and the media about India's "vested interest" or "ulterior motive" in giving Sri Lanka a helping hand during a crisis.

Later, in August, India's objection to the docking of the Chinese survey vessel Yuan Wang 5 at Hambantota port for a week, was viewed as an affront to Sri Lanka's sovereignty until India categorically denied that it had put any pressure on Sri Lanka to rescind the permission given to the vessel to dock. India also said that Sri Lanka, being a sovereign country, could take whatever decision it wanted. The relationship is now on an even keel.