A new poll found Republican Rep. Marsha Blackburn trailing former Gov. Phil Bredesen of Tennessee by double digits in the race for a US Senate seat in the state.

The poor showing from Blackburn in the poll indicates a Republican-held seat could flip in what is expected to be a wave of Democratic wins this year.

Former Gov. Phil Bredesen of Tennessee, a Democrat, is leading Republican Rep. Marsha Blackburn by double digits in the race to replace Sen. Bob Corker, who is retiring later this year.

A poll conducted by Middle Tennessee State University and released Thursday found that 45% of 600 registered voters surveyed in Tennessee favored Bredesen, while 35% said they would back Blackburn. Another 17% are undecided.

The poll found that among voters who identified as independent, preference for Bredesen is 12 percentage points higher than for Blackburn. One-fifth of Republican respondents said they would cross the aisle and vote for Bredesen, compared with just 5% of Democrats who said they would do so for Blackburn.

Blackburn's performance in the poll suggests that Democrats are within striking distance of flipping a long-held Republican US Senate seat in November.

When Corker last year abruptly decided to bow out of running for reelection, Blackburn quickly jumped in the race to take his place. Blackburn is much more conservative than Corker, drawing the bulk of her support from the GOP base.

Ken Blake, the director of the MTSU poll, told the Tennessean that Blackburn could run into trouble if she were to find herself needing to soften some of her stances.

"If she ends up having to kind of attract some moderate Democrats or Republican-leaning independents, it could be a challenge," Blake said.