Suppose there is a state or congressional district where no candidate gets 15% of the vote. That is unlikely to happen this year, of course, but it could in a year where the field is more crowded and the candidates' support is more split. Does no candidate get any delegates?
The new threshold is set at half of whatever the top candidate gets. It does not go to full proportionality, though in practice if such a thing were to happen there would probably be many candidates who cross the "threshold" and it would differ very little, mathematically, from no threshold at all.
And if one candidate gets exactly 15% but no one else does, does that candidate get all the delegates?
Yes, if only one candidate finishes above 15%, even if that is only very narrowly, then they sweep all of the delegates from that CD or state. Much of Biden's strength comes from the fact that polling has suggested he could sweep southern rural areas even if he's doing very poorly nationwide.
