DAVID GREENE, HOST:
OK, I'm not telling you anything you don't know. This has been a year with lots of partisan wrangling in state legislatures, and certainly here in Washington.
LINDA WERTHEIMER, HOST:
The cause, some political experts say, is a primary voting process that produces too many candidates with extreme views. Reformers in a few states have changed the rules. They believe holding open primaries - which allow people of any party to vote - will help more moderate candidates.
GREENE: NPR's social science correspondent Shankar Vedantam often comes by to provide us with hard data that tests our assumptions and helps us understand the stories of the day. And Shankar's back with us. Shankar, hello.
SHANKAR VEDANTAM, BYLINE: Good morning, David.
GREENE: Give us a brief reminder. Why are reformers trying to change the primary system here?
VEDANTAM: Well, the concern is that the political process has been hijacked by partisans, David, and they're doing it by having outsized influence during primary elections. Only one in five Republicans and Democrats shows up to vote in primary elections, and these voters tend to be the most partisan voters. And as a result, candidates with the most strident views tend to appeal to these voters, and those are the candidates that tend to win.
GREENE: You get to more extreme views, and less agreement when they come to Washington or state legislatures.
VEDANTAM: Exactly. And so a lot of reformers have thought about the idea that if you open up elections, you might end up getting more moderate candidates. So if you have a Republican primary, for example, but you allow Independents and Democrats to come in and vote for the Republican candidate, potentially now, you have a broader electorate. And so if I'm a moderate candidate, I'm going to do better in that electorate.
The trouble is there has been a trend in recent decades to move from closed primaries to open primaries across the country, at the very same time that there has been an increase in political polarization.
I spoke with Nolan McCarty. He's a political scientist at Princeton University. He's just analyzed thousands of state primary elections. He's asked two questions: Do open primaries produce more moderate candidates? And second: Do districts that switch from a closed primary to an open primary produce more moderate candidates?
NOLAN MCCARTY: And answer to both of those questions was no, that the type of primary system that a state uses has almost no connection with levels of polarization of their state legislatures.
GREENE: So, Shankar, it's so interesting. What he's saying is you open up primaries, let everyone vote - Democrats, Republicans, independents. The expectation is you'll produce more moderate candidates. His evidence is it's not happening. Why not?
VEDANTAM: Well, the problem, David, is that even though you change the rules to allow moderates to play a bigger role in the primary, moderates don't actually come out to vote in primaries.
VEDANTAM: McCarty's point is that partisans are the ones who know the most about politics. They care the most about politics, and regardless of the rules, they're the ones who show up and vote.
Now, I should say there's some efforts in California and other states to have a new kind of open primary called a top two primary, where there's a single primary for both political parties, and the top two finishers, regardless of party, run against one another in the general election. Now, there's probably too little data to exactly know what the effect of these changes are going to be.
In California, for example, McCarty thinks we might be seeing less gridlock, not because politicians have become more moderate, but because one party - the Democrats - have come to thoroughly dominate the state.
GREENE: OK. So, California, you know, trying a different way to change the mechanics of the election. I mean, do McCarty and other social scientists, you know, look more broadly at some other ideas that might produce moderate candidates, if the answer is not open primaries?
VEDANTAM: Well, McCarty had a very counterintuitive suggestion when I asked him that question, David. He said what we actually need are stronger political parties. Now, that sounds weird, because the problem is political polarization.
VEDANTAM: But his point is that political parties are basically in the business of winning elections. And they know that if they nominate moderate candidates, they are more likely to win elections. Ideologues, on the other hand, David, are much less interested in winning elections, and they're more interested in moving their party and the country to one side or the other. This is especially true on the right, where we often see Tea Party candidates now challenging establishment Republican candidates.
GREENE: Shankar, we should say, though, that there are many people who like the fact that ideology plays a big role in politics. They like that, you know, they focus more on their beliefs, what they believe in, and not necessarily the mechanics of winning or losing an election.
VEDANTAM: Yeah. I think that's right, David. And it's also possible that one side is right and one side is wrong on some issues. So moderation might not always be the right answer. But I think many Americans look at what's happening in Washington, and what they see is paralysis, and they're blaming polarization for such paralysis.
One of the things McCarty thinks we can do is limit the amount of influence that special interest groups have in primaries, because these interest groups have figured out that by controlling the primary, you're able to control the whole political process. McCarty thinks by limiting the amount of money they're able to pour into primary elections, you can return more power to the political parties, who will be in nominate more moderate candidates.
GREENE: Shankar, thanks, as always, for coming by.
VEDANTAM: Thank you, David.
GREENE: Shankar Vedantam. He regularly joins us to talk about social science research. You can follow him on Twitter @HiddenBrain. And you can follow this program @nprgreene. Steve is @nprinskeep. The program is @MORNINGEDITION. Transcript provided by NPR, Copyright NPR.