If you are like me, this measure is the one that has delayed me sending in my ballot. I just can't decide how I feel about this and as an economist, there is not a whole lot in economic theory that seems to help. But here is my best attempt. Comment away.
The basic premise of the species homo-economicus is that we are essentially rational utility maximizers. This creates a problem if we think about the marginal impact of a single vote (basically zero) versus the cost of voting (not zero). But if we expand our understanding of the typical voter's utility function, it is not hard to believe that a sense of civic duty, a desire to play a part no matter how small, etc. creates benefits beyond just the ability to determine the outcome of elections. So the basic theory is pretty simple - the voters that determine elections are the ones in the middle and the politician that can appeal to the greater fraction of these middle voters will win.
This makes a lot of sense if you take as given that most people will vote or at least that the proportion of people that will vote is relatively constant throughout the political spectrum. But this assumption is not valid. So economic theory has to incorporate the fact that there are particular issues that will motivate particularly non-centrist voters and will change the proportion of populations that actually vote throughout the political spectrum. This assumption appears empirically valid. The success of Rovian political theory seems to show that voters can become more motivated through political appeals to the things that they care deeply about.
To this I'll add the somewhat controversial claim that we are, to ever increasing degrees, self-segregating along political lines. Take Oregon; the increasing proportion of registered Democrats in the state and the overwhelmingly democratic Willamette valley seem to suggest that Oregon is destined to become heavily democratic.
So what would an open primary look like in such a state? Well in an open primary, standard political economic theory would seem to suggest that the fighting would be over who could be the most popular center-left candidate. But with more than one of these battling over, say 60% of the votes, one could easily imagine one or two center-right candidates finding a relatively easy path to the final. A more modern theory might predict a number of hot-button issue candidates trying the mobilization strategy which, if successful could leave the center behind in a general election.
I have seen arguments that we shouldn't worry because in the state of Washington every single open primary they have had has led to a Democrat v. Republican general election. Is this good news? If it is then we should not change things because the current system delivers basically the same thing. Is it bad news? Well imagine a general election with two democrats. What would be the optimal strategy: pander to the base and mobilize, or try and capture the most right-leaning votes you can. I can imagine both could be winning strategies. Also, the fact that Washington has yet to have a same party general election may simply be the artifact of a two party system that is one, well-financed, and two, deeply ingrained in the psyches of voters.
So here is the rub - does this make our political process more fringe driven or less and does it matter? I think the answer to the first question depends on the marginal impact of mobilizing the base relative to the marginal impact of capturing the middle. I worry that as we become more self-segregated the marginal impact of mobilizing the fringe will begin to dominate. I think the answer to the last question is yes, it does matter. The health of a representative democracy, I believe, depends directly on how effectively the interests of the entire society are represented. And I guess I am as yet unconvinced that our two party system, for all of its obvious faults, is not the best way to ensure this happens. I know that this is an academic's response, but I think I'll wait for more evidence before I vote for a change.
But ask me again tomorrow.... any thoughts that could help me out?