We’re coming into what promises to be the most expensive election in the history of American politics. Everyone is raising money and people in the campaign finance reform camp are setting their hair on fire over it. President Obama may miss his original goal of raking in a billion dollars, but it might not be by much. So the Republicans must be spending up a storm themselves, right?

Maybe not.

Even as experts predict that the 2012 presidential race will be the most expensive in U.S. history, a funny thing is happening on the way to the Republican nomination: It’s becoming one of the cheapest primaries in a more than a decade.

The top nine Republican candidates spent $53 million through September, compared with $132 million spent at the same time four years ago. The sum is even lower than totals reported during the same period in the 2004 and 2000 primaries — when most candidates still were abiding by campaign spending limits in order to receive public matching money.

In the crowded Democratic primary in 2004, the candidates had spent $58 million through Sept. 30, 2003. Four years prior, a primary field of ten Republican candidates had spent $68 million in the first three quarters of 1999.

The analysis in the Washington post goes on to note that the historic number of debates we’ve had thus far has negated the need for the extensive television advertising we’ve seen in past campaigns. In part, I’m sure that’s true. It’s given everyone plenty of time at the podium and massive amounts of earned media as multiple 24 hour news networks slice and dice every word. But I think there’s more at work here.

More than ever we’re seeing the profusion of “web ads” being put out by campaigns. The more flamboyant they are the better. But the funny thing is, the campaign only has to pay to create the ad and put it up on a single campaign site. Then they use free resources like Twitter and Facebook to get some buzz going and getting everyone to link to it. This, in turn, becomes catnip for the cable news shows which then begin to show the advertisement in endless loops to the target audience of those voters who pay the most attention and are thus the most likely to vote.

Remember Herman Cain’s “smoking man” ad with Mark Block? It was possibly the most viewed and most talked about political campaign ad of this cycle. Do you know how many times Team Cain paid to run it on the air?

Zero.

But you saw it, didn’t you? And so did everyone else. Campaigns are getting smarter and playing both the social media networks and the news teams like a fiddle. And in the process, they keep their powder dry and save their resources for the long war to come next summer. Pretty smart, really.