The mixed bag which our political parties use across the various states to select candidates has always been a bone of contention. In what is probably a healthy development, we seem to be moving toward a somewhat more standardized system of primaries rather than caucus arrangements. (Democrats will have 37 primaries next year and Republicans 42.) But the other question which is still clearly in flux is whether those primaries should be open – allowing independents, or even members of the opposition, to participate – or closed to party members only.

Mark Siegel, at the Washington Post, tackles the question today, coming at it from the perspective of someone who helped close the primary process for Democrats over the years but is now having second thoughts.

A significant factor in the polarization of American politics is the “closed primary” — contests that restrict participation to registered party members. This is an unanticipated consequence of what was meant to be a positive reform of the Democratic Party nominating system, preventing strategically mischievous “crossover voting.” As Democrats changed state statutes to close their primaries, the laws generally affected Republican primaries as well. By excluding independent voters, who generally are ideological moderates, the restrictions narrowed the internal debate within both parties and accelerated the radicalization of American politics.

I am not a bystander to this process. I have served as executive director of the Democratic National Committee and as a member of three Democratic delegate selection reform commissions that incrementally moved to restrict participation in our party nominating processes. We changed our rules in 1972 to prevent more incidents like that year’s Michigan Democratic primary, at which Republicans voted in large numbers for Alabama Gov. George Wallace. Our intent was strategic and honorable: Why should Republicans be allowed to vote to nominate a racist, unelectable Democrat?

Leaving aside the blatant partisanship and insulting tone taken in the second paragraph, Siegel ironically seems to answer his own question. If you’re going to take that attitude toward the Democrats’ nominating process, one might argue the same for the other side, asking why Democrats should be allowed to push a big government, tax and spend candidate in the GOP race? As they say, if the shoe fits…

But the author does touch on another aspect to the question. Hard core partisans are likely to scoff at the question, seeing as much differentiation as possible as a good thing. But is there a down side to keeping independent (or the dreaded word… “moderate”) voters out of the primary process?

The two chief arguments against this are easy to find. First, how small of a “tent” do you want and how damaging is it to have a variety of opinions and ideologies represented in the primary? Second, and perhaps more of a pragmatic notion, is the issue of electability – a subject which seems to have become a dirty word of late. After the base from each party selects the nominees, the center picks the winner every four years. At what point does purity cross the line to the Pyrrhic?

We have a bit of a laboratory to examine these patterns in the form of the New Hampshire primary. Due to the rules of the road in the Granite State it’s fairly easy for independents to vote in either primary. This produces an interesting, somewhat oscillating set of results over the years.

In a cycle where there is no incumbent president running, (such as in 2008) both parties have contended primaries. This can result in independents who would typically lean a bit more to the right showing up for the GOP vote and those leaning a bit more to the left clustering at the Democrats’ ballot box. The result of this is a winner which will skew a bit more toward the base. But in contests such as next year’s, when there will effectively be no Democratic primary of any significance, independents – including the more centrist or even libertarian or left leaning voters – tend to flock toward the Republican race because, well… it’s the only action in town. This can result in a bit more of a moderate vote.

So which one produces the more desirable result? And, perhaps more importantly, which one produces a candidate most likely to not only win the primary race, but the general election. Here’s the record of who has won in New Hampshire going back to the late 1940’s. You be the judge.