It challenged professor warren to come out and stay away. she said no, they're okay. as long as they're factually correct. so then there is a group, oh my goodness. i don't like that. >> the race is still a competition. both sides claim credit for initiating the pac. warren believes she made it enforceable. >> at first, brown says no. he says that is not possible. it's stuff. >> all i can say it's my idea. i'm glad that professor warren joined in. good thing for massachusetts. >> i hope this is not a game about who wants to take credit. >> the agreement requires candidate to shell out money fr...