In 1940, when the Independence of India and Burma was imminent, the Zomi in India (now Mizoram) gave their opinion to Sir Robert Raid, the High Commissioner of Assam that they would be better off if they were attached to their kinsmen in Burma. The proposal was recommended by Sir Robert Raid to London that the Hills of Arakan, Pakkoku and Chittagong, Chin, Naga, Lushai, North Cachar and Mikir areas; parts of Chindwin; the hill areas of Manipur; the hill area of Sadiya, the west bank of Chindwin and, hills of Tripura should be unified under one administrative unit. Reid’s plan was approved by Sir Winston Churchill but when World War II was over, the Conservative Party lost in the Parliamentary election and the Labour Party who was not conversant of the problem came into power and the problem remained unresolved.
This resulted into the formation of Mizo Union on April 9, 1946 for the re-unification of Zo tribes. On 24 September, 1946 at Kulikawn, Aizawl, the Mizo Union held its first General Assembly in which they adopted a resolution that all areas inhabited by the Zo viz. Lushai Hills, Chin Hills and some areas of Manipur and North Cachar be included in the proposed Lushai Hills District. Mr. Vanlawma, the General Secretary of Mizo Union played a dominant role in the movement.
At Lakhimpur, on 21 November, 1946, the Mizo Union (MU) held a meeting which was attended by Zo representatives from Cachar, Lushai Hills and Manipur in which they unanimously resolved that all Zo areas in Cachar District, Manipur, the Chittagong Hill Tracts and the adjacent Chin States should be amalgamated with Lushai Hills into one Unit and be designated as Zoram District. The justification for the resolution was the common culture, language, religion and geographical continuity shared by all the areas and most importantly, because the people of all these districts shared the same ethnic origin.
On 3rd January, 1947, the Mizo Union wrote to the President of the Constituent Assembly of India to inform him that the Lushai Hills District be excluded from the Constituent Assembly because the Mizo Union wanted to frame a constitution of their own and decide for themselves whether to stay under the British protection, or to form an independent state, or to join Burmese Chin Hills and form a separate province within Burma. However, adverse to the idea of Vanlawma, Khawtinkhuma and Saprawnga signed an agreement in July, 1947 to come under India. Hence, the initial movement that began at the time of British rule, for Zomi Re-unification and led by Vanlawma and Pachhunga, lost momentum and direction.