Vice President Joe BidenJoe BidenTop union offers backing for Ellison in DNC race John Kerry to teach at Yale on global issues Ellison needles Perez for 'unverifiable' claim of DNC support MORE will campaign for Democratic Senate candidate Cory Booker just five days ahead of Election Day.

Biden will hit the trail for Booker in New Jersey on Oct. 11. The Newark mayor is leading in every poll of the race, but the most recent survey showed his lead over Republican Steve Lonegan dropping to just 12 points, from more than 20 points in most preceding polls.

Still, Booker is the heavy favorite to win in the deep-blue state.

Biden has acted as closer in campaigns before, most recently making a similar last-minute campaign stop for Sen. Edward MarkeyEd MarkeyOvernight Tech: GOP chairman to propose high-skilled visa overhaul | Zuckerberg's 5,700 word letter | Tech lobbies gear up ahead of internet fight Senate Dem blasts GOP for trying to repeal broadband privacy rules Judge orders release of EPA nominee’s emails MORE (D-Mass.) shortly before his win in the Massachusetts Senate special election.

Markey was facing slightly tighter polls but a similarly favorable atmosphere in Democratic Massachusetts, and won by ten points on Election Day.