Here is the web page for the Arizona group that is attempting to qualify an initiative on the November 2012, to pass a top-two open primary law. The map misleads viewers into thinking that Nebraska has a top-two open primary. Actually, Nebraska has semi-closed primaries for President, Congress, all state executive offices, and all partisan county offices.
The adherents of the Arizona initiative, if asked about this, would probably say, “Yes, but Nebraska has non-partisan legislative elections”, and that would be true. However, non-partisan elections are not the same as top-two open primary systems. Although vocabulary in this area of election law is frequently confusing, all writers about primary systems define “top-two Primary” to be a system in which party labels appear on ballots, yet parties don’t nominate candidates.
Party labels on the ballot are the single most important determinant of how voters vote. Political science research has confirmed this for over half a century. A system without party labels, such as the Nebraska legislative election system, is therefore very different from any system in which party labels appear on the ballot. Nebraska has had non-partisan elections for the legislature since 1934. Nevertheless, political science research has shown that even the Nebraska legislature, in recent years, has behaved in a very partisan manner. Thanks to Mark Rogalski and Christina Tobin for the link.