Sikkim as a British Protectorate
In 1890, the Anglo-Chinese Convention, an agreement signed between the British and Chinese monarchies, Sikkim was declared as a “protectorate” of the British Empire. Over the next few decades, Sikkim became a full-fledged Princely State in British Colonial India.
Post-1947: Indian Protectorate
When the British left India, all Princely States, including Sikkim, became independent nations. A popular vote was conducted, over whether Sikkim should become a part of the Indian Union, and the people rejected the proposition. Sikkim continued to be an independent nation but in 1950, Prime Minister Jawaharlal Nehru facilitated the signing of the Indo-Sikkim Treaty, under which Sikkim became an Indian protectorate. Sikkim would continue to be a sovereign nation but in matters of external affairs, defense and communications, it would defer to India.
Merger with India and Chinese Reaction
While Sikkim became a Constitutional monarchy under Indian suzerainty, anti-royal protests continued to break out in the Himalayan state. The Sikkim National Congress, a pro-India group, led the protests against the Chogyal of Sikkim. In 1975, the Prime Minister of Sikkim urged the Indian Parliament to merge Sikkim into the Union. In April, the Indian Army marched into Gangtok and disarmed the palace guards. A referendum was held and the people of Sikkim voted overwhelmingly, with a 97.5% majority, to join the Indian Union. In May 1975, the Kingdom of Sikkim became the 22nd state in the Union of India.
China, however, refused to acknowledge the democratic referendum as legitimate. Beijing continued to regard Sikkim as an independent nation, which it regarded as being occupied by India. China claimed that the referendum was conducted by India under military occupation.
After Sikkim’s accession to India, several high-level meetings were held between New Delhi and Beijing. Despite visits from then External Affairs Minister Atal Bihari Vajpayee, Prime Ministers Rajiv Gandhi and PV Narsimha Rao and Chinese premiers Li Peng and Jiang Zemin, Sikkim continued to be a thorn in Sino-Indian relations. It was finally in 2003 that a compromise between the two nations led to a thaw. China agreed to officially recognize Sikkim as an Indian state on the condition that India declared Tibet as a part of China. However, the biggest development on the India-China freeze over Sikkim came with the opening of the ancient Himalayan pass Nathu La in 2006 as a border crossing. The two nations agreed to allow trade through the route, which laid to rest the dispute over whether Sikkim was a part of Indian territory.