"If they're too big to fail, they're too big."
-Alan Greenspan
It is interesting that the Citizen's United case (decided January 2010) came so close in time to the financial crisis, in particular the Dodd-Frank Act (signed July 2010).

The "too big to fail" issue means that the government needs to take steps to break up extremely large corporations. Yet the Citizens United decision created a clear conflict of interest — Congresspeople and Presidential candidates will receive a large percentage of campaign contributions from the very same companies, which means they need to do everything they can to avoid upsetting those companies.