If you’re looking for the name Chuck Hagel to run across your cell-phone screen as Barack Obama’s running mate, get ready for disappointment. Not only will Hagel not accept a VP invitation from Obama, he won’t bother to endorse him, as many thought he might. Instead, Hagel will quietly complete the last few months of his Senate term before retiring:

Sen. Chuck Hagel, a Nebraska Republican who is one of John McCain’s closest friends — but who has been mentioned as a potential running mate for Democrat Barack Obama — is sitting out the presidential contest, according to his spokesman, Jordan Stark. (USA TODAY’s Kathy Kiely reporting and writing.)

“Senator Hagel has no intention of getting involved in any of the campaigns and is not planning to endorse either candidate,” Stark said in a statement to USA TODAY.

Suggestions for cross-party candidates have flown over the past two months as both Obama and John McCain try to reach for centrists and independents.  McCain actually has plenty of centrist credibility already, though, and needs a running mate that will energize the GOP base.  Obama, on the other hand, has no real track record of bipartisan work and could have used a disaffected Republican to steal a march on McCain in the fall.

Of all the potential candidates for that job, Hagel probably presented the best choice.  A genuine war hero turned war critic, Hagel would have given Obama some immediate credibility on military affairs and perhaps better footing on foreign policy than Obama has at the moment.  Hagel also could have provided Obama with some cover on Iraq for changing his policy, allowing Hagel to take some of the heat from the Left if circumstances forced him to make more adjustments.  Having Hagel at the Democratic convention would have given Democrats a powerful moment, especially as the running mate.

USA Today says that Hagel’s choice to remain neutral is a striking development in terms of McCain’s campaign, but no one expected Hagel to endorse McCain or any other Republican this year.  We did expect a Zell Miller moment from Hagel in support of Obama, especially after the two teamed up for their CODEL to Iraq and Afghanistan.  The Nebraska Senator had a lot of critical things to say about the Iraq policy and the Republican efforts before he left, but he’s suddenly gotten very quiet — and according to USA Today, intends to stay that way.

What happened on his trip with Obama?  Something seems to have changed very suddenly.