Complex sentence: Term-limited in 2000, he ran for Governor of Montana in the 2000 election but lost in the Democratic primary to Mark O'Keefe, who went on to lose the general election to Republican Judy Martz.
Split into simpler sentences: Term-limited in 2000, he ran for Governor of Montana in the 2000 election. He lost in the Democratic primary to Mark O'Keefe, who went on to lose the general election to Republican Judy Martz.