Just months after the Citizens United decision came down, the U.S. Chamber of Commerce got together with Republican strategists to cook up a scheme for using untraceable corporate money to take over state legislatures. They were particularly intent on influencing the 2010 elections, because the politicians who came into office at that time were charged with redrawing the boundaries of legislative districts. The result: there are 17 seats in the US Congress that - if districts were impartially drawn - should be Democratic, but with the help of corporate-funded gerrymandering, are Republican.
http://www.epi.org/blog/corporate-power-in-state-legislatures-produces-a-gerrymandered-congress/