The 2012 presidential and congressional elections will be the most expensive on record, the nonpartisan Center for Responsive Politicsestimates — though not by much. The Center predicts, based on data from 18 months of fundraising and spending, that the elections will cost $5.8 billion, an increase of 7 percent from the 2008 cost of $5.4 billion. But outside spending, which is soaring while presidential candidate spending declines, is a wild card that makes predictions tricky.

So far overall in the first 18 months of the 2012 cycle, $2.2 billion has been spent, compared with $2.4 billion in 2008.

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