Critically elucidate the various phases of merger of Sikkim into Union of India while keeping in focus the 35th and 36th amendment of the Indian Constitution.

From a hereditary monarch in 17th century, Sikkim became British Protectorate subject to British Paramountcy. In 1947, Sikkim rejected joining Indian Union.
When China invaded Sikkim in 1950s, Nehru offered support to them. The treaty signed between the two made Sikkim hand over its external relations to India, allowed the stationing of Indian troops and prohibited the kingdom from “dealings with any foreign power”.
It gave Sikkim status of a protectorate with Chogyal as the Monarch. After Chogyal’s death he was succeeded by his son. There was a growing dichotomy among the people and the new ruler. Namgyal wanted full sovereignty but majority of the people wanted removal of monarchy and a democratic set up along with accession to Union of India.
1973, a historic agreement was signed between the Chogyal, the Government of India and the political leaders of Sikkim, which acknowledged the important role of the people in the affairs of Sikkim.
In 1974, the Sikkim Assembly passed a Government of Sikkim Act, 1974, which paved the way for setting up the first ever responsible government in Sikkim and sought Sikkim’s representation in the political institutions of India. India passed the 35th Amendment Act inserting a new Article-2A {Sikkim to be associated with Union} and a 10th schedule.
In 1975, the Kazi Lhendup Dorjee (Prime Minister in Sikkim) appealed to the Indian Parliament for a change in Sikkim’s status so that it could become a state of India. There was a referendum in1975 which approved  abolition of monarchy and complete merger of Sikkim, leading to 36th Amendment Act, wherebyArticle-2A and Xth schedule were repealed and name of Sikkim wasadded as a state under first Schedule of the Constitution. With this, Sikkim emerged as India’s 22ndstate on 26th April, 1975.