So Georgia's State school superintendent race draws 15 candidates. A few of those, like, if my hunch is correct, the US Senate Democratic primary, are likely to be candidates sent in by the "big name" to drain the populist candidate of energy and support.
If this isn't a perfect example of why we need preference voting, I'm not sure what is. Here is more on IRV
An instant run-off, although unpopular with people whose job is to get people elected (since they get more work and make more money when you have a primary-run off) would save money for the state and create incentives for more positive campaigning and alliance building by politicians.
It would also force more real politic thinking by voters. By forcing voters to rank order their preference they have to acknowledge trade offs in their own thinking; trade offs are how we make decisions and find compromises to get things done.
Plus any good economist will tell you much of the best and most fruitful moral and public policy thought has been done on Preferences, Value, Choice, and Welfare.
So getting our policy selection mechanism to better reflect where all the action is at in terms of decision making and policy compromise might be a useful change.