Complex sentence: Orchard has never held political office in Canada, but has been involved in leadership conventions for both the Progressive Conservative Party and the Liberal Party, and is perhaps best known for his campaign to oppose the Canada-U.S. Free Trade Agreement.
Split into simpler sentences: Orchard has never held political office in Canada, but has been involved in leadership conventions and other political activities. He is perhaps best known for his campaign to oppose the Canada-U.S. Free Trade Agreement.