Ernst, a lieutenant colonel in Iowa's national guard and first-term state lawmaker, has received encouragement from Iowa Gov. Terry Branstad (R) and Lieutenant Gov. Kim Reynolds (R) to run for the seat.

She joins an already-crowded field of fairly unknown GOP candidates, after all of the state's well-known Republicans took a pass on the race. Declared candidates include David Young (R), who until recently was Sen. Chuck GrassleyCharles (Chuck) Ernest GrassleyGrassley: Dems 'withheld information' on new Kavanaugh allegation Feinstein calls for hold on Kavanaugh consideration Grassley releases letter detailing Kavanaugh sexual assault allegation MORE's (R-Iowa) chief of staff, as well as former U.S. Attorney Matt Whitaker (R) and conservative radio host Sam Clovis (R). Businessman Mark Jacobs (R) is also looking at a run.

ADVERTISEMENT

The eventual primary winner will go on to face Rep. Bruce BraleyBruce Lowell 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), who Democrats have rallied around as their standard-bearer. Braley already has more than $2 million in the bank for the race after raising more than $1.25 million in the last three months.

A survey released Wednesday by the Democratic firm Public Policy Polling shows Braley leading his GOP opponents by 9-3 points, though much of that lead may be due to their relative anonymity in the state.