Hagan's decision to fundraise with Biden indicates she's less worried about being tied to President Obama than other Democrats facing reelection this cycle. Obama nearly won North Carolina in 2012, while he was badly beaten in other states Democrats face reelection like Arkansas, Alaska and Louisiana.

Hagan has posted strong fundraising numbers heading into her first reelection bid: As of the end of June she had $4.2 million in the bank. She has not yet announced her third quarter fundraising numbers.

Republicans believe beating Hagan could be the turning point in winning back Senate control. North Carolina state House Speaker Thom Tillis is the GOP front-runner, though Baptist Minister Mark Harris (R) and Tea Party favorite Greg Brannon (R) are also in the race.

This post was updated at 10:30 a.m.