In a display of the unpredictability of the race, conservative groups are falling on opposite sides of the Republican Senate primary in Nebraska.

FreedomWorks, a tea-party-affiliated group that has backed candidates like Sens. Ted Cruz, R-Texas, and Rand Paul, R-Ky., announced Monday that it has endorsed former state Treasurer Shane Osborn.

That news came just days after Midland University President Ben Sasse landed the second of two coveted conservative endorsements from the Club for Growth and Senate Conservatives Fund.

Last cycle, in another Cornhusker State open-seat race, all three groups backed Don Stenberg, who ended up losing the GOP nomination to now-Sen. Deb Fischer.

They are running next year to replace retiring Sen. Mike Johanns. The race is rated Safe Republican by Rothenberg Political Report/Roll Call.