NPR recently featured an interview with Nolan McCarty of Princeton who has recently compared states that have open primary systems (where everyone can vote) or closed primary systems (where only partisans can vote) and found that there is no discernible difference in the ideological extremity of candidates from either system. They both tend to produce ideologically extreme candidates. This is because moderates do not tend to take advantage of the opportunity to participate in open primaries which are instead dominated by ideological partisans, just like closed primaries.
I recommend taking 5 minutes to listen to the interview.
Once again, voters have only themselves to blame for the massive amount of polarization in Congress. If ideological moderates were to participate more, we might get more more moderate politicians elected to office. Instead we have a political system where only the ideologically extreme partisans participate, and lo and behold, we get an ideologically extreme set of politicians representing us.
This also has implications for Utah’s “Count My Vote” initiative that is trying to change Utah’s caucus-based partisan primary system to a more open primary system. There are very good reasons to support such an initiative (increasing the opportunities for access and participation being chief among them) but thinking that it will result in less ideological candidates coming out of Utah should not be one of them.