Lessig was quite emphatic about his intent to select his successor (the VP) based on Party principles - no discussion on Constitutional principles at all in his platform. Why would Sanders or Warren want to be his VP? If they knew they would become President as soon as Lessig enacted his own brand of mandates, and that those mandates were important enough to get him elected, then why wouldn't they take up the mantle of proposing those mandates in the first place?