Former Nebraska Treasurer Shane Osborn is likely to announce his candidacy for the Senate within the next few days, according to usually reliable GOP insiders.

While in the Navy, Osborn was detained by the Chinese in 2001 after the plane he was piloting was forced to land following a collision with a Chinese fighter jet. Osborn was elected state treasurer in 2006, but did not seek re-election in 2010. He was involved in a messy divorce.

The open Senate seat is likely to generate a good deal of interest — especially since Gov. Dave Heineman announced this weekend he would not run, creating a wide-open race for the GOP nomination.

Most observers are waiting to see whether Rep. Jeff Fortenberry and/or Nebraska GOP National Committeeman Pete Ricketts, who lost a Senate race to Democrat Ben Nelson in 2006, enter the contest. Other Republicans are also mentioned, though the open governorship could draw considerable interest.

The state Democratic Party looks very weak these days, and it wouldn’t be surprising if the potentially most formidable Democrats opt to run for state office rather than the Senate seat.