Measure 90 in Oregon is on the ballot, which will create a top 2 open primary system where voters pick between all candidates running for an office and the top 2 candidates, regardless of the parties the candidates are or the percentage the winning candidate receives. So theoretically, there could be a general election between two Republicans or two Democrats. This is the system in use in California and Louisiana.
Supporters believe that it will decrease partisanship and increase voter choice. One of the strongest arguments supporters of “top 2” make is that non-affiliated voters are shut out of the process because the major parties close their primary process to non-party members.
However, the “top 2” open primary system limits voter choice because minor party candidates, unless they’re wealthy or well-known, will not have an opportunity to enter the general election. Also, this will essentially make political parties meaningless and empower special interests. Finally, this is essentially an incumbent protection racket because the anti-incumbent vote can be split up and made irrelevant. Finally, if you’re a partisan Democrat and the two general election candidates are Republicans, you’re disenfranchised and have no choice on the ballot.
It would be easier to just have regular party primaries, but require as a condition of state funding of the primary election that they be opened to non-affiliated or independent voters.
Here’s an interview on a YouTube show between supporters and opponents of Measure 90.