Considering the gravity of the risk in Wall Street banks being too big to fail, the financial reform bill passed by the US Senate in 2010 may have been influenced too much by the financial interests. It can thus serve as a good case study for how a republic can be subject to too much influence from the moneyed interests. It could be asked, moreover, whether there is an inevitable trajectory that a polity undergoes from being a republic to becoming a plutocracy (ruled by the wealthy).
The full essay is at "Anti-regulatory Wall Street Lobbyists After the Financial Crisis."
Sources: http://www.nytimes.com/2010/05/23/us/politics/23lobby.html?scp=2&sq=financial%20lobbying&st=cse ; http://www.nytimes.com/2010/05/24/business/24reform.html?hp ; WSJ (May 26, 2010).