[RobertLS]

Why do Republicans favor unlimited corporation election funds for politicians but want to limit union election funds?

well as most Republicans are in the south, they want to limit the union funding as it defeated them in a war during 19th century, and as corporations are opposing the union, it is very natural that they support them. Freedom from Union oppression!

Also there is a good chance is the corporations win, they will re-introduce slavery, so it is a win-win scenario.