Why did Australia federate?
Australia decided to federate because prior to 1901, it did not exist as a sovereign nation. The motivation to bring the colonies together included the need to construct a greater domestic market via eliminating tariff obstructions on commerce between the colonies. The impetus also lay in the desire to uphold the prevailing concerns of the colonies whilst relying on a national government to take responsibility for Australia’s broader interests such as security, defence and foreign relations.
FENNA, A., ROBBINS, J. & SUMMERS, J. 2014. Government and politics in Australia, Frenchs Forest, N.S.W., Pearson Australia.