He lost for the same reason all the others lost. Conservatives tired of outright traitors stayed home on election day.
In one to two more cycles, it will go back GOP again. Iowa has long been known for sending an all GOP Delegation with exceptions from time to time.
When you abandon or abuse or take for granted your base, you lose.
Good riddence.
Moron. Or maybe I should have said "moran" since spelling is beyond you as well as thinking.