Rep. Bruce BraleyBruce BraleyOPINION | Tax reform, not Trump-McConnell feuds, will make 2018 a win for GOP Ten years later, House Dems reunite and look forward Trump: Ernst wanted 'more seasoning' before entertaining VP offer MORE (D-Iowa) has a narrow lead over Iowa state Sen. Joni ErnstJoni Kay ErnstHouse passes bill to curb presidential pensions Senators push mandatory sexual harassment training for members, staff We must do more to celebrate women small business owners MORE (R), according to a new poll from Quinnipiac University.

Braley leads Ernst by 44 percent-40 percent in the live-caller poll in the hotly contested race.

That's a bump for Ernst since the last time Quinnipiac polled in March, when she was just starting to gain traction in the primary and before his "farmer from Iowa" comments surfaced.

Two other polls conducted immediately after the primary, one by a nonpartisan pollster and one by a Republican, found her with narrow leads. But those might have been picking up on post-primary enthusiasm for Ernst.

The live-caller poll of 1,277 registered voters was conducted on landlines and cellphones from June 12-16 and has a margin of error of plus or minus 2.7 percentage points.