See my post #23. The 1986 US Senate race in California should have resulted in a Republican pickup. Incumbent Alan Cranston was vulnerable, and there were about 12 candidates vying for the nomination. Of these, 11 were conservative and one--Ed Zschau--was a leftie.
The conservatives campaigned hard against one another, but eventually one, Bruce Herschensohn, emerged as the frontrunner. Lesser candidates began to drop out and support Bruce, but Mike Antonovich continued to run negative ads against Bruce late in the campaign.
Zschau won by taking only a third of all the votes cast, and since there was no runoff, he got the nomination--and went on to lose the race.
And Bruce Herschensohn was nominated for the U.S. Senate in 1992 giving us Barbara Boxer.