Unless he isn’t the only Walter F Williams in Center Valley PA.
I hadn't seen the claim for this before.
The Walter Williams that subs for Rush is Walter
E. Williams. I don't see one listed as a donor for Mitt. And Wikipedia shows the quotes and WaPo article where he endorses Ron Paul as his favorite. Mr. Williams is also regularly begged to run for president himself (which I think would be outstanding). And Ron Paul says that someone like Williams is who he would want for VP.
So I think Williams didn't donate to Mitt. Not that I have any big problem with Mitt though. I like all the candidates who aren't named Giuliani.