Polls have shown Hagan is vulnerable to a challenge, but North Carolina Republicans have yet to find a strong candidate to challenge her. Rep. Renee Ellmers (R-N.C.) is also considering a bid, as are some state lawmakers, though none are expected to make a decision on the race until the state legislative session wraps up in June.

Hagan posted a strong fundraising quarter, announcing earlier this week that she'd brought in $1.6 million and has $2.7 million on hand for the race.