Policy is influenced by interests AND ideas.

While the populist rage against financial institutions continues, it is well to keep in mind that these special interests could not have captured government policy by money alone. It was also necessary that there was widespread acceptance of a worldview they could wrap around their causes. Dani Rodrik makes the point:

No-one could deny that interest groups play a role in shaping policy. But I would argue (i) that the identity of the groups that get to exercise power and (ii) the manner in which their interests are advanced are also determined by prevailing world views about the proper role and functions of government. On the first point, isn't it the case that the reason trade unions, say, have lost power in recent decades is the ideology of deregulation which swept Washington, D.C.? Or that U.S. auto makers have been unable to get large-scale import protection because this was a no-no in the prevailing ideological climate?

So, while campaign finance reform is important, it would not be enough to change the direction of history. We need to challenge, and ultimately to change, conventional wisdom. Read Rodrik's whole post here.