Dave Weigel has this analysis at Bloomberg Politics on the California U.S. Senate race for 2016. Because incumbent Democrat Barbara Boxer won’t run for re-election, it is likely that four or five prominent Democrats might run for the seat. The analysis says if there are two strong Republicans, it is possible the two Republicans might place first and second in the primary, eliminating all Democrats from the November ballot due to California’s top-two system.
Of course, Democrats understand this, and the party is virtually certain to pre-select no more than three leading Democratic candidates and to use every possible device to squeeze out any other prominent Democrats. This is why top-two systems actually create less competition than normal systems do for the members of the two major parties. Thanks to Thomas Jones for the link.
IPR Note: See Editorial: IPR Opposes Proposition 14 in California