Persuasion Versus Influence
People have been talking about Hillary Clinton's defense of lobbyists and their money at the YearlyKos convention last week.
In the wake of this, people are wondering aloud Whether or not it's really plausible whether certain politicians would really change their minds based on whether or not they receive fat checks from certain parties.
What I don't see people saying is that these questions are irrelevant.
I don't think you need to persuade a politician to change their mind on something in order to wield influence. With so many politicians, one does not waste time trying to make change when you can get more bang for the buck by keeping things from changing. In other words, you don't support politicians with some quid pro quo, rewarding them for cozying up to your preferred policies. You find the politicians who already agree with your policies, and you give them the money they need to run successful campaigns.
Those against taking lobbyist money tend to cut themselves out of races before they even begin. Edwards, who has always sworn off lobbyist money (and has, like Romney, plenty of his own), and challenged all the other candidates present to do the same, is a rare exception to the rule.
Consider it a form of natural selection for political candidates. No persuasion needed.