The chart below shows spending by outside groups in three categories: independent expenditures, electioneering communications and communication costs.
As the chart makes clear, the 2004 election marked a watershed moment in the use of independent expenditures to try to sway voters, with most of that new spending coming from the national party committees.
The 2010 election marks the rise of a new political committee, dubbed “super PACs,” and officially known as “independent-expenditure only committees,” which can raise unlimited sums from corporations, unions and other groups, as well as wealthy individuals.
Source: Total Outside Spending by Election Cycle, Excluding Party Committees | OpenSecrets
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