they wouldn't have to buy in. that's a big difference, because barack obama's vision was not to leave 10 million people uncovered. he wanted every single person in this country covered. my plan would do that. your plan would not. >> they do not have to buy in. they do not have to buy in. >> you just said that two minutes ago. you just said two minutes ago that they would have to buy in. you said they would have to buy in. are you forgetting what you said two minutes ago? i'm fulfilling the legacy of barack obama and you're not. >> that'll be a surprise to him. >> reporter: after that heated exchange, the other democrats on stage quickly jumping in. >> this is why presidential debates are becoming unwatchable. this reminds everybody of what they cannot stand about washington. scoring points against each other, poking at each other, and telling each other that your plan, my plan -- >> yeah, that's called a democratic primary election. that's called an election. that's an election. you know? this is what we're here for! it's an election.