You're missing the point. Limiting campaign contributions is not a part of this. The point is to anonymize donations so that there can be no way for the candidate to correlate a contribution to a donor. That way the quid pro quo that is implicit in campaign contributions would go away. Politicians would have to go back to representing voters again.
I'm saying it's not the quid pro quo. I'm saying that generally are multiple sides to an issue, and people want to represent their side. A corporation would just fund the person who represents the views that are most inline with theirs. Corporations would tell the candidate what they feel is important, and then when he espouses the views the candidate receives anonymous donations.
And by corporation I don't just mean GE etc, I'm thinking of any group of people who have a shared ideology and are working to influence policy.
