01/04/2012 01:02 pm ET Updated Jun 18, 2012

The Tea Party Fever Has Broken

Perhaps the most important undercurrent in American politics that the Iowa Republican caucuses reveal is that the raging Tea Party enthusiasm fever of 2010 that led to historic Republican election victories has broken.

Participation in the Iowa Republican caucuses was strong. Over the past four years, participation in the Iowa Republican caucuses only slightly outpaced the state's population growth. Four years ago, 118,696 people participated in the Iowa Republican caucuses compared to 122,252 in 2012, an increase of 3.0%. Over this same period, the eligible population increased from 2.20 million to 2.25 million, an increase of 2.4%.

Not unexpected, turnout for the 2012 Democratic caucuses was significantly lower than 2008. The Iowa Democratic Party reports that "more than 25,000" people participated in the 2012 Democratic caucuses, compared to 236,000 in 2008.

But, participation in the Iowa Republican caucuses should have been stronger. If the Tea Party was still in full swing, we should have seen higher turnout propelled by their enthusiasm.

Instead, it was Independents who participated in the Democratic caucuses four years ago that enabled turnout in this year's Iowa Republican caucuses to keep pace with the 2008 levels. These Independents preferred spending their evening participating in an actual election contest rather than in a party organizing meeting. A pre-caucus PPP poll indicated that 15% of prospective Republican caucusgoers reported participating in the Democratic caucus in 2008. With 236,000 people voting in the Democratic caucus, that means the Republican caucus were inundated with 35,400 more participants that were active on the Democratic side four years ago.

The media entrance polls further support that some people who participated in the Democratic caucuses in 2008 participated in the Republican caucuses in 2012 -- although the pollsters did not directly ask this question. In 2008, only 13% of polled caucusgoers reported being an independent. In 2012, this percentage of independents increased to 23%. (These folks predominantly supported Ron Paul, followed by Mitt Romney.) Without these crossover Independents, turnout in the Iowa Republican caucuses would have declined. And without them, Romney would not have won his squeaker victory.

Politicians running for office this November should take notice. The extraordinary Tea Party enthusiasm that buoyed Republican candidates in 2010 is unlikely to repeat itself. And on top of weakening Tea Party enthusiasm, we are assured that November turnout will be higher for pro-Democratic groups, such as young people.

Of course, it ain't over until it's over. This is only a single state to draw inferences from. The upcoming primaries will likely provide a better picture of the levels of Republican enthusiasm at this stage in the election cycle. Without a contested Democratic nomination, we have no clear indication of Democratic enthusiasm levels. It may be that a general malaise will overtake supporters of both parties come November, or one or both sides will catch fire as the campaign shifts from a choice among Republican candidates to a choice between Obama, the eventual Republican nominee and other potential third party candidates lurking in the wings.

CORRECTION: The estimated number of Independents who participated in the 2008 Democratic caucuses who participated in the Republican caucuses has been revised from 59,000 to 35,400.