Complex sentence: Governor Hamilton was instrumental in seeing that the association, which was both a political and a social organization, expanded throughout the state, and in the winter of 1831 and spring of 1832 Hamilton held conventions and rallies throughout the state to mobilize the nullification movement.
Split into simpler sentences: Governor Hamilton was instrumental in seeing that the association, which was both a political and a social organization, expanded throughout the state. In the winter of 1831 and spring of 1832, the governor held conventions and rallies throughout the state to mobilize the nullification movement.