Good, detailed reporting from the Pittsburgh Post-Gazette on Supreme Court deliberations on an attempt by the Libertarian Party of Oklahoma to allow any registered voter to vote in an LP primary. The whole piece is worth reading, but here are some excerpts:
Justice Antonin Scalia said the open-door policy favored by the Libertarians meant that "we don't have any policies; we just want to nominate someone." He said such a policy "destroys the whole purpose of letting people run under a party label."
In Oklahoma, political parties are….free to invite independents to take part in their primaries, but they may not put out the welcome mat for voters registered in another party. Without that ban, the justices were told, one party could "poach" the voters of a rival party, making the results in both primaries less reflective of the will of loyal party members.
But several justices questioned the "poaching" theory. Justice David H. Souter wondered whether a Democratic or Republican voter disaffected enough to vote in another party's primary wouldn't simply stay home on Primary Election Day if he didn't have that option.
The justices seemed divided over the constitutional issue in the case—whether the law infringes Oklahomans' First Amendment right to political association.
….Scalia suggested that voters who are "ashamed of the L word" could keep their options by registering independent and then voting in the Libertarian contest on Primary Election Day.
Several justices worried that a ruling in favor of the Libertarians would mean that the Democratic and Republican parties also could hold open primaries…..
[The LP's lawyer] suggested that the justices could rule narrowly for the Libertarians because, as a small party, they were especially burdened by early registration deadlines and other election rules.
[Link via Rational Review.]