By one estimate, more than $1 billion has already been spent on the 2010 midterm elections, and that number could nearly quadruple before all is said and done.

The Center for Responsive Politics tells The Hill that they expect spending of $3.7 billion when all is said and done.

“We fully expect this will be the most expensive midterm election ever in U.S. history,” said Dave Levinthal, a spokesman for the Center for Responsive Politics (CRP). “Not only do we expect it to exceed the high water mark set in 2006, but this could very well obliterate that number when all is said and done.”



The 2006 midterms, which gave Democrats back control of the House and Senate, cost more than $2.8 billion, according to CRP estimates. 

The Citizen’s United decision by the Supreme Court, which allows for unlimited political spending by corporations on political campaigns, could play a huge part in that money tidal wave.

The CRP estimates that the Republican-leaning Chamber of Commerce could spend $75 million during this election. 

Unions are also expected to spend big, with AFSCME and the AFL-CIO kicking in close to $100 million.