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The Trail: Key Senate race neck-and-neck as midterms near

Let’s turn to the campaign trail as candidates prepare for one last week of campaigning. Our new NBC News/Marist polls indicate many of these key Senate races will come down to the wire on election night.

The best news for Democrats is in Arkansas, where incumbent Sen. Mark Pryor has closed the gap with Congressman Tom Cotton to sneak within the margin of error. But in Kansas, all of the national GOP support has boosted Sen. Pat Roberts, jumping down from double-digits to just 1 point behind independent Greg Orman.

There are big problems for Democrats in the biggest races: in Iowa, State Sen. Joni Ernst is inching closer to 50% in her race against Congressman Bruce Braley; and Colorado Democratic Sen. Mark Udall is behind Republican Congressman Cory Gardner in a state where the majority of voters will cast their ballots by mail.

And, finally, North Carolina–where Democratic Sen. Kay Hagan has lost her lead over State House Speaker Tom Tillis. Can she swing the momentum back in her favor before Nov. 4?

Andrea Mitchell Reports - The Trail and North Carolina

The Trail: Key Senate race neck-and-neck as midterms near