For a democratic merger of countries the necessary conditions are contiguity and a common language. Closer home, West Pakistan and East Pakistan were not sustainable precisely because they were neither contiguous nor had a common language. As for the European Union, please remember the countries of Europe have not merged. There has merely been a removal of trade barriers and a formation of a unified currency to benefit trade between them. Each country in Europe has its own language and government. Europe is not and cannot be a federal state, with one constitution and one flag.
Coming to the Indian subcontinent — or the region historically known as Bharat — it is largely made up of present-day India, Pakistan and Bangladesh. Bharat was really a continent, containing countries quite often at war with each other. Prior to 1857 these various entities were ruled by kings. After 1857, Bharat became a British colony. The officers of the British Empire, over a period of nine decades, bound the countries of ‘Bharat ‘ (British India) together through the use of the English language, the railways, the judiciary and, of course, the army.
To English colonisers British India was one country, a concept that the English-educated Indians, who later became the political leaders of this country, internalised in turn. For them India was one country, in reality things were different — India was actually a continent with 20 languages, many kingdoms and many governments.
Ultimately, when the British left, they handed over power to two nations instead of one country. India had to accept the prospect of losing a part of its territory in order to gain complete independence. Pakistan had to accept an artificially created ‘Muslim region’ instead of a conglomeration of Muslim-majority states.
Today there is no common bond between India and Pakistan. Therefore let us bury the idea of ‘Akhand Bharat’ once and for all.