Why has she not been expelled from the party?
She has by the primary voters. She'll never be elected to anything as an (R) again. Democrats don't want her either. She's all washed up, so don't just go away Liz. Go away totally crushed and humiliated.
I believe the State of Wyoming Republican Party did expel her from their ranks.
“Why has she not been expelled from the party?”
Because many in the party leadership have the same convictions. They are just more careful not to expose them.