Establishment Republicans have been beating back Tea Party challengers in recent primaries. Both factions can make an electability argument. Tea Party candidates rightly point out that their base is more enthusiastic than the rest of the electorate, while mainstream Republicans correctly argue that the Tea Party is turning off swing voters.Both these arguments appear to be correct. In a survey of Iowa voters that we conducted last night:
- 68% of strong Tea Party supporters said that they were more enthusiastic about voting than they were in previous years.
- This compares to 42% of the population at large, and only 35% of those strongly opposed to the Tea Party saying that they were more enthusiastic about voting .
- 90% of strong Tea Party supporters say that they will definitely vote, compared to 71% of voters at-large.
- Voters consistently over-state their likelihood to vote, but at least in terms of self-reported turnout likelihood, Tea Party supporters have a 19% advantage.
On the other hand, among voters who routinely spit their tickets, 54% say that they would be less likely to support the Republican candidate if that candidate had close ties to the Tea Party, while only 11% of the ticket splitters said that they were more likely to support a candidate associated with the Tea Party.So how do you weigh these two factors? Does the increased enthusiasm of Tea Party supporters make up for the swing voters they will turn off? It’s hard to say, but it’s fun to do some back-of-the-envelope math. The strong Tea Party supporters account for 18% of the electorate in Iowa. Ticket splitters account for 26%. According to this survey, strong Tea Party voters are 19% more likely than voters at large to say that they will definitely vote. So this translates into a 3.4% bump that can be attributed to increased enthusiasm among Tea Party backers. Of course many of those would vote for the Republican candidate whether or not that candidate had close ties to the Tea Party, so it is impossible to say how many of those 3.4% would be net new votes.Ticket splitters make up 26% of the population, and 54% of them say that they are less likely to vote for a candidate associated with the Tea Party. 11% say that they are more likely to vote for a Tea Party candidate, so that translates into a net minus of 43% in support among the ticket splitters. 43% of a group that comprises 26% of the electorate gives us an 11% decrease in support for the Republican candidate if Republicans nominate someone with close ties to the Tea Party.These two calculations aren’t apples to apples. As noted earlier, self-reported turnout likelihood is notoriously unreliable, and as for the swing voters we don’t know how many of them would not have voted for the Republican candidate in any circumstances. Still, the large difference between the two numbers does seem to indicate that Republican operatives should be hoping for wins by mainstream Republicans in tonight’s primaries.Democrats can just breathe a sigh of relief that for once they aren’t the ones with the bitter inter-party fight.