BRIAN WILLIAMS, NBC NEWS: Let's take your theoretical bracket here of a Clinton/Trump race in the general. Where do the young voters go? Especially the young voters we have seen in such sweeping and impressive numbers at Sanders events.
CHRIS MATTHEWS: That's up to people like Bernie Sanders and Elizabeth Warren.
Elizabeth Warren has not been a big part of our conversation [in 2016]. But she could help rally them to Hillary in one way or another. She could get out there and stump for her. That would change everything. They are disembodied, they're not part of the Democratic party yet. They have to be brought into this campaign. Not as Democrats but as those who want to have a role in the general election. I think Elizabeth Warren is the key. I think she really is.