Show me the money - 2008 Election

Here is the 2008 Election Cycle Giving by Industry to Candidates. The question arises, What is the reason industries and Political Action Committees give to a particular candidate? Note: Barak Obama states in almost every speech that he takes NO PAC money. Based on what you see here is that true? Both democratic candidates state that Republican campaigns are financed by special interests and big oil. Conversely, The Republican manta is that Democrats are financed by Trial Lawyers , Insurance, and Pharmaceuticals. Republicans and Democrats both say the other is financed by Lobbyists.