Monmouth national poll: Clinton's lead shrinks, Biden has the momentum.

[Why]

Sanders has exposed Clinton's campaign as not being very strong because she has failed to control the contest against a low caliber opponent. The door has been left ajar and Biden looks to be in a very good position to take advantage of the situation. He can be a really strong opponent to Clinton, much stronger than Sanders would ever be. Clinton needs to be very worried about Biden and needs to very quickly work out a way of getting back the support that is drifting away from her.