He has already made up his mind, and it's a lost cause to try to change it.
Many attempts were made to shake his fidelity to the lost cause of the Stuarts, but he continued indomitable to the end.
Russie is a lost cause.
I don't think he's the lost cause you're making him out to be, she said, disturbed.
"She's a good girl," Giovanni said, "but she's a bit of a lost cause.
Rhyn was a lost cause from the beginning.