It gave the Congress party unusual strength because:
(i) A coalition tries to accommodate all those who join it. Therefore, it has to strike a balance on almost all issues thereby leading to compromise and inclusiveness. The Congress was able to accommodate variety of views and thereby the opposition could not find major issues to attack Congress with.
(ii) There is a greater tolerance of internal differences and ambitions of various groups and leaders in a coalition. The Congress was able to do this during the freedom struggle and continued after independence. Thereby leaders would not leave the Congress and be accommodated within it.