Former state Treasurer Shane Osborn is the first Republican to enter the wide-open GOP primary for Nebraska’s open Senate seat.

In an email to the Lincoln Journal-Star, Osborn campaign manager Dave Boomer — who has managed campaigns for GOP Rep. Lee Terry — said Osborn has filed papers with the Federal Election Commission and will be holding kickoff rallies at a later time.

In the race for the seat of retiring GOP Sen. Mike Johanns, Osborn and other potential candidates had been awaiting a decision from Gov. Dave Heineman. The term-limited governor took himself out of the running over Memorial Day weekend.

The other top candidates looking at the race include Midland University President Ben Sasse and 2006 Senate nominee Pete Ricketts. Rep. Jeff Fortenberry, the most likely of the state’s three GOP members of Congress to enter the race, announced last week that he would not run.

Osborn became famous in 2001 when, as a naval aviator, a plane he piloted collided with a Chinese plane in international waters.

Rothenberg Political Report/Roll Call rate this race Safe Republican.