Four Pathways for Democrats Against Trump — With or Without Biden

President Joe Biden's stumble in last week's debate has the world buzzing once again about the possibility of a new presidential candidate emerging from a brokered Democratic convention next month — a political spectacle that hasn't happened since 1952. The most likely way for that to happen would be for Biden to step aside, something he's said he has no intention of doing. Party rules also leave open the possibility that another Democrat could challenge him at the convention, but there would be nearly insurmountable obstacles to doing so. In the case of an emergency, Democrats could even swap out candidates after their convention.

Here's how the various scenarios might work.