When we discuss voter turnout - mostly in 2305, though it certainly applies to 2306 - we point out that turnout varies depending on the types of election. We also point out that the composition of the electorate varies depending on the election.
This is especially true for primary as opposed to general elections.
Primary elections - as you have hopefully already seen - are party elections. It's how party identifiers determine who their party's candidates for the general election are. Notice what the graph is telling us.
The more ideologically consistent the voter - the more likely he or she will vote in a political primary. The more mixed - meaning the more moderate the voter - the less likely this is the case. This tells us that candidates for general elections are selected by ideologues. This guarantees that those candidates will be ideologues also - since that's what it takes to win primary elections.
What's more, moderates have little ability to determine what candidates will be on the ballot on the general elections because they opt not to vote in primary elections.
There's a school of thought - that I tend to agree with - that looks at primary elections as the driving factors behind ideological and party polarization.
This graph provide evidence why that's the case.
