I love how the antiplain idiots try to justify someone else quitting. Palin had her reasons to resign. Very good reasons just like Dole had his reasons. I happen to agree with both their reasons. They both resigned for their own reasons with the voters in mind. Your failure to accept that fact makes you a hypocrite. Deal with that also.
Yes, he quit AFTER he was the presumptive nominee and after he completed five full terms. Palin quit (in her first term) almost three years before the first primary. Some 1.5 years later, she still isn't a candidate for anything.
Deal with it.