What will happen to all those Santorum, Paul, and Gingrich supporters when the Republican party nominates Mitt Romney this summer? In Spring of 2008, droves of Hillary Clinton supporters declared that they would not, indeed could not, vote for Barack Obama in the general election. Instead, they would cast their ballots for John McCain.
How many of them did that?
Using data from the 2008 Cooperative Campaign Analysis Project (that I ran with Simon Jackman from Stanford University), I looked at the general election vote choice as reported by people who voted for Clinton (or Edwards) in the primaries compared to people who voted for Obama in the primary. At the end of the day, 20% of those Clinton primary supporters report they voted for McCain. Roughly the same amount of Edwards’s voters defected to McCain.
In the hotly contested Democratic conteest in 2008, one out of five voters who were not on the soon-to-be nominee's bandwagon never got on. But most did.
What happens when we examine Republican primary voters from 2008 and look at their general election votes conditional on which candidate they voted for in the primaries?
One very interesting number jumps out from these data: 29%. Nearly a third of the Republican primary voters who cast ballots for Ron Paul in 2008 defected in the general election and voted for Barack Obama. Defections among supporters of the other candidates from 2008 are in the single digits. Overall, only9% of Republican primary voters defected to Obama in the general election.
We can’t say with certainty that Paul’s 2012 supporters will behave similarly to his voters from 2008, or whether the 80% of Clinton and Edwards supporters from 2008 will vote with Obama again, but history is typically a pretty good guide in politics. The good news for Romney is that 93% of Mike Huckabee’s supporters in 2008 ended up voting for the more moderate McCain in the general election. And indeed, this is what I heard from Santorum, Perry, and Bachmann voters around Iowa this week as I went from one campaign stop to another asking them whether they would vote for Romney if he got the nomination.
“Yeah,” they said, closing their eyes for a moment and rocking their heads from side to side. “Yeah, I will,” they added in resigned fashion.
“What else am I gonna do?”