Ranked-Choice Voting
Ranked-choice voting (RCV) means the voter votes for candidates in order of preference. If there is no clear majority winner, the lowest-ranked nominee is eliminated, and their votes assigned to those voters’ next-highest=ranked candidate, until there is a clear majority winner.
This may not be great for general elections; it is easily used to oust a sitting party for momentary purposes.
But it would be great for primaries! It would not throw the baby out with the bathwater, if poles were taken more often, giving voters a chance to express their preference without committing to a sudden change in government.
Single-issue candidates, though they may not be eventual winners, would be promoted as champions of their cause, and the other candidates would see the swell of support for that cause.