Complex sentence: He was a member of the New York State Assembly in 1844 and 1845, having been chosen as a Whig and in 1846 was state senator and a delegate to the New York constitutional convention.
Split into simpler sentences: He was a member of the New York State Assembly from 1844 to 1845. He joined the Whig Party and in 1846 was state senator and a delegate to the New York constitutional convention.