Iowa state Sen. Joni Ernst (R) edged 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) in second-quarter Senate fundraising — but she badly trails him in cash on hand following an expensive primary.

Ernst raised $1.78 million in from April through June, slightly more than the $1.7 million Braley brought in. But Braley, who didn't have a competitive primary, has stockpiled $2.7 million for the race, far more than the $1.1 million Ernst has in the bank.

That haul marks a big uptick for Ernst, who'd struggled with fundraising from the start of the campaign. But Braley's big cash edge could have an impact on a race that's emerged as a key Senate battlefield heading into the heat of the general election.

A poll of registered voters released Wednesday by NBC News and Marist found Braley and Ernst tied at 43 percent apiece.