FILE - In this Aug. 3, 2019, file photo, Senate Majority Leader Mitch McConnell, R-Ky., addresses the audience gathered at the Fancy Farm Picnic in Fancy Farm, Ky. Ex-Marine pilot Amy McGrath, who seemed to be gliding toward a primary victory in Kentucky, has come under heavy fire from both directions in the closing days of the Democratic contest to determine who challenges Republican Senate Majority Leader Mitch McConnell in the fall. (AP Photo/Timothy D. Easley, File)

FILE - In this Nov. 6, 2018, file photo, Amy McGrath speaks to supporters in Richmond, Ky. McGrath, The Ex-Marine pilot who seemed to be gliding toward a primary victory in Kentucky, has come under heavy fire from both directions in the closing days of the Democratic contest to determine who challenges Republican Senate Majority Leader Mitch McConnell in the fall. (AP Photo/Bryan Woolston, File)

FILE - In this Dec. 27, 2019, file photo, Democratic candidate for U.S. Senate Mike Broihier poses for a photo in Frankfurt, Ky. Ex-Marine pilot Amy McGrath, who seemed to be gliding toward a primary victory in Kentucky, has come under heavy fire from both directions in the closing days of the Democratic contest to determine who challenges Republican Senate Majority Leader Mitch McConnell in the fall. Broihier and Freshman state Rep. Charles Booker support a universal basic income and Medicare for All — ideas that McGrath has resisted. (AP Photo/Bruce Schreiner)

FILE - In this Feb. 19, 2020, file photo, state Rep. Charles Booker advocates for the passage of Kentucky HB-12 on the floor of the House of Representatives in the State Capitol in Frankfort, Ky. Ex-Marine pilot Amy McGrath, who seemed to be gliding toward a primary victory in Kentucky, has come under heavy fire from both directions in the closing days of the Democratic contest to determine who challenges Republican Senate Majority Leader Mitch McConnell in the fall. Booker recently released his first TV ad that says a “real Democrat” is needed to take the fight to McConnell, the top-ranking congressional Republican who is seeking a seventh term. (AP Photo/Bryan Woolston, File)

This combination of 2019 file photos shows U.S. Rep. Thomas Massie, R-Ky., left, in Washington, and GOP challenger Todd McMurtry in Frankfort, Ky. Kentuckians are accustomed to bare-knuckled politics, but the Bluegrass State brawl between a Republican congressman and his primary challenger has turned especially ugly. Massie and McMurtry have battered each other in the conservative 4th District along Kentucky's northern tier. The winner of the June 23 primary will be a prohibitive favorite to keep the seat Republican in November. (AP Photo/J. Scott Applewhite, Adam Beam)