someone making 1,000 phone calls for you could do nothing for you, or they could gain you 1,000 votes. Comparatively, you'll know (or be able to know) exactly what money donated to you has gained you.
The ad you buy with $1,000,000 could do nothing for you or it could gain you 1000 votes. Money, like phone calls, posters put up, or doors knocked on, is a means, not an end. There's no obvious exchange rate for any of these into votes, and it's votes that matter. I would actually reverse your claim, it's easier to measure the impact of calls or knocks, since you get some immediate feedback (even if it's subjective) whereas when you buy an ad you not only can't get feedback till the next poll, you can't tell how much of the change in the polls is due to statistical variance, any given ad, recent news coverage, etc.
Only if you assume that the manner in which that outrage comes to exist is unchanged. Considering the relative lack of outrage over people like Adelson, Fries, or Simmons in this cycle so far, I think we can safely assume that the "outrage-bar" has been raised.
Well I don't actually think that outrage is the limiting factor over the efficacy of donations/expenditures, it was Zamfir who said he did, at least mostly. But it's true, I don't think there's much to be outraged over with those latest donations.
There are problems, this is true, but I've never felt that because something isn't easy, that we should accept it the way it is.
No disagreement here. But I'm not saying change is hard. I'm saying no matter how noble the goal, many proposed changes are bad because of the unintended consequences (though the pro-incumbent impact of some of those changes is likely anything but unintended when proposed by elected officials!). That doesn't mean there aren't good changes possible, nor does it mean we should give up.

