Complex sentence: He was first elected to the Canadian House of Commons in the 1872 Canadian election and became Whip in the caucus of Alexander Mackenzie and helped bring down the Conservative government over the Pacific Scandal.
Split into simpler sentences: He was first elected to the Canadian House of Commons in the 1872 federal election, and became Whip in the caucus of Alexander Mackenzie. He helped bring down the Conservative government over the Pacific Scandal.