Julian Zelizer is a professor of history and public affairs at Princeton University. He is the author of "Jimmy Carter" (Times Books) and author of the forthcoming book "Governing America" (Princeton University Press).

As Americans read about the flood of private money that is going into the current presidential campaign, most can't help but shake their heads in disgust about how our democracy functions.

With all the talk about changing Washington, voters are shrewd enough to understand that if contributors give this much money to the candidates in both parties, there is little chance that Washington will be much different in 2013.

Americans tend to be cynical that campaign finance reform will ever work. The conventional assumption is that politicians will never be willing to fix the system and they will circumvent any laws that come their way. Trust in government continues to plummet.

Yet we must remember that there have been moments when positive change happened. The most important episode in the history of campaign finance reform took place in the aftermath of the Watergate scandal that brought down President Richard Nixon....