Presidential debates have become reality TV, complete with commercials.  This week, there are 10 Democratic candidates still onstage and two more in the wings. Polls suggest that potential voters have more choices than they need in a party sharply divided by factions.  

Party leaders can’t remember when there were so many undecided voters this close to  February’s Iowa caucuses, suggests Washington Post National Political Correspondent Jenna Johnson.  

Democratic party official Elaine Kaymark adds that Democratic leaders “allow too many people who really don’t have any business running for president.”  

Policy differences range across the political spectrum, from centrists like  Joe Biden and Pete Buttigieg, to leftist progressives like Bernie Sanders and Elizabeth Warren. But the debate format gives them only a minute to answer complex questions on health care, foreign policy, etc.

So how do voters make up their minds? Political science professor Patrick Stewart studied the outcome when Republicans faced the same problem in 2016.  He says TV viewers are most influenced by how candidates appeal to the audience sitting inside the arena.  

He says it’s ultimately about candidates’ charisma and excitement, whether they laugh at jokes they tell, and whether they boo or applaud their opponents.

But that’s not the end of the story. Candidates who have the resources are campaigning hard to reach their supporters in Iowa and  other swing states.