The Iowa caucuses are the first actual election results in the presidential campaigns. In the Republican race, they show that Sen. Ted Cruz (R-TX) can do well in regions where conservative Christians have historically flexed their influence. Donald Trump, however, did worse in these areas.
Here are three graphs that tell the story (followed by some stats on the Rubio third-place finish).
First, I take a look at how Donald Trump did in each county. To tap into the influence of the conservative Christians in each county, I use the vote received by Mike Huckabee in 2008. Donald Trump generally did better than Huckabee `08 did in most counties. He received a higher percentage of the vote in all but the most conservative and rural counties (see the blue line). Overall, however, Trump did worse in counties that have historically supported conservative Christian candidates.
What about Ted Cruz? We see a key to his victory in this graph. He did better in Christian Right counties than in other counties. The counties Huckabee ’08 did well in eight years ago were the ones Cruz did well in. That said, because of the number of other candidates in this year’s field (such as Ben Carson and Huckabee), Cruz fared worse in these counties than Huckabee did. Cruz made up for this by doing better in other parts of the state. In other words: Cruz had a broader appeal than Huckabee did when he won eight years ago.
Of course, Trump and Cruz were running against each other, not against Huckabee `08. This third graph shows the difference between the two candidates in each country. In counties with the strongest conservative Christian base gave Cruz double-digit win over Trump. There were only a handful of counties in which Trump did that to Cruz. In most of the regions where the Christian Right is less influential, the two candidates were neck and neck.
Finally, a word on Marco Rubio’s third-place finish. The Rubio campaign should be very pleased with the result and where the votes came from. Rubio won five counties, and they may indicate his broader appeal among Republican voters. He won the three counties in the Des Moines area (Polk, Dallas, and Story counties). He also won the Johnson County, home of the University of Iowa. He received the top votes in Scott County, too, which is the county for Davenport.
Bottom-line: Cruz mobilized conservative Christian areas; Trump did well everywhere but the most ardent Christian Right counties; and Rubio did best in the most populous, diverse parts of the Hawkeye state.