Complex sentence: The New Zealand government have wanted to let go of its colonial territories but prior to 1965, the Cook Islands had no political system, and the general population rarely took any interest as to what the country's future should be.
Split into simpler sentences: The New Zealand government wanted to give its colonial territories independence but, prior to 1965, the Cook Islands had no political system. The general population rarely took any interest as to what the country's future should be.