Did you know that, even if McCain Fiengold was still the law, rich people would be able to pay for, and air, any advertisement they wanted as long as they did it themselves? One reason you, and all liberals, should support the CU decision is it allows middle class people to get together and do the same thing rich people can.
Limiting direct campaign donations, but not spending, is what is skewing the current system. Romney is bringing up a valid point that candidates should be able to vet ads that appear in their name. Ron Paul just filed a law suit against a group that is airing an ad that they are claiming was made by him. The example used in the OP was just one example of the good that comes from not limiting donations, it gives people who think that there needs to be change more power to make a difference.
At this point in time, with Republicans experiencing a resurgence of conservative activists, disrupting the party by allowing them to support the candidates they want instead of the ones that are put forth by the establishment could probably produce similar results to what occurred happened to the Democrats in the 1960s, more Democrats getting elected.
By the way, it is a fallacy that money always benefits conservatives, the (D)s easily outspent the (R)s in 2010, it just didn't make a lot of difference. I will also point out that the single most expensive gubernatorial campaign in CA history resulted in the guy with no money being elected.
I did know that. The relevant part of McCain-Feingold was a limit on corporate rather than individual spending. It didn't affect all spending by organizations though, just certain kinds of organizations.
You present corporate spending as though it were spending by the owners of corporations, which include middle class people who own mutual funds. Such persons still tend, weighted by their dollar ownership, to be much wealthier than the average American. Even so, there is little evidence that political spending by corporations is responsive to the political views of small shareholders. Rather, it is spending made at the direction of corporate officers who are fairly unresponsive, particularly in this arena, to many of the owners.
You're right that money isn't everything in politics. Some candidates, such as Giuliani in 2008 or Perry in 2012 spend a great deal of money while earning few votes indeed. However, money isn't nothing either. I continue to wish that it was more difficult rather than less to use money to influence politics.
It's certainly true that money sometimes benefits Democrats in politics. My impression is that it tends to benefit Republicans over Democrats but I certainly could be wrong. Again, though, my primary objection to the use of money in politics is that it takes power away from voters rather than from Democrats.