The winner of the GOP primary is expected to face Kerrey, a popular former governor and senator who initially opted out of running for retiring Sen. Ben Nelson's (D-Neb.) seat, but changed his mind last week.

Another poll released Tuesday by Rasmussen, a GOP polling firm, showed all three Republicans in the primary — Stenberg, Bruning and state Sen. Deb FischerDeb FischerDem labels infrastructure ‘top thing’ Trump can accomplish Senators press the FCC on rural broadband affordability Smart investments in America’s future MORE — beating Kerrey by double digits in a general election. In the case of Bruning, the Republican lead was 22 points over Kerrey.

The Rasmussen poll of 500 likely voters was conducted March 5 and had a margin of error of plus or minus 4.5 percentage points.