It's a tale of two graphs. Neither is wrong, but the same question generates a very different answer.
At Mother Jones, Dave Gilson ran some numbers and came up with a graph that charts spending in presidential campaigns over time, adjusted for inflation. It shows a fairly steadly climb over time, escalating suddenly in 2008 to historic highs.
Jonathan Bernstein at the Washington Post suggested a missing variable, noting that the population has greatly expanded over time. Bernstein then pulled out the back of an envelope and concluded that 1896 was a lot pricier than Gilson allowed, once you adjust for the number of voters in play.
"Let’s see...the Republican Party overall seems to have spent an estimated $16 million in 1896, with the McKinley campaign spending $6-7 million. Inflation alone makes us translate that $6M to over $150M, far lower than what Barack Obama spent in 2008. But then if we also think about a per-vote, or potential vote it starts sounding more like today’s numbers."
Seth Masket took Bernstein's observation and ran with it, producing a second graph that shows Bernstein's tweak. The extremes are reduced, and today's pattern seems to fit much more into historical trends. 2004, for instance, no longer looks like a new escalating spiral, and instead falls back below 1968 levels.
The peaks and valleys themselves should also be tied to the competitivness of the election, including primaries. 2008, for example, produced expensive and close fought nomination fights in both parties, as did 1968. In contrast, 1996 had no challenge for the Democratic side, and very little for the GOP.
And yet even here, the story may be incomplete. This data apparently does not include outside spending. PAC spending on behalf of candidates prior to 2002 and the Super PAC spending after the 2010 rule changes are excluded.
With President Obama appearing poised to top the $1 billion line and the GOP scrambling to keep up via Super PACs, 2012 could prove to be historically expensive by any measure.
We will need another graph.
Eric Schulzke writes on national politics for the Deseret News. He can be contacted at firstname.lastname@example.org.