(AP) — Compared with the acrimonious primary campaigns elsewhere, the race for the GOP Senate nomination in Nebraska sounds like two nice guys running for local Rotary Club president.

But make no mistake, Nebraska is a new front in the bitter national struggle inside the Republican Party between established leaders determined to maintain control and right-wing insurgents trying to change the party’s direction.

Behind the public geniality, party powerbrokers including Senate Minority Leader Mitch McConnell and his allies are quietly backing Shane Osborn, a Navy veteran best known as the pilot of an American spy plane forced down by the Chinese military in 2001. They are steering donors his way.

Tea party groups are endorsing Ben Sasse, the president of Midland University in Fremont, and sending him contributions, too.