She won't even say his name during her public appearances, which speaks volumes about what she thinks if the creep.
But yet...
Daily Caller Whines That Increasingly Irrelevant Palin Hasnt Endorsed Romney
And you're right, why should she, especially after THIS:
I heard her with Hannity last night. When asked if she would support the “presumed” Republican nominee, she didn’t mention Romney’s name but said, as she noted she has said in the past, that she would vote for anybody that opposes Obama.
She knows who has sand bagged her and led the campaign against her and isn’t going to give them anything but a back handed endorsement.