The Bengalee nation had struggled for democracy, secular values and national rights for years. The military rulers of the Islamic Republic of Pakistan tried to deny the democratic and national aspirations of the Bengalees and carried out systematic genocide in the name of religion. As a result, the struggle of the Bengalee people began from language movement of 1952 to the armed resistance in 1971, which ultimately led to the emergence of Bangladesh as a secular democratic nation state.
The following fundamental principles enshrined in the Constitution therefore evolved from its tradition and experience of this popular struggle.
(Socialism was the other fundamental principle. However this principle was generally considered to mean social justice particularly for the disadvantaged.)
The people of Bangladesh are still continuing their struggle to retain these principles against many odds.