Who are possible replacements for retiring Nebraska Sen. Mike Johanns?

So freshman Sen. Mike Johanns didn't even need a full term in the Senate to decide he was bored and wanted out. The former two-term governor, who cruised to a relatively comfortable 58-40 victory over Democrat Scott Kleeb in 2008, has announced his intention to retire at the end of his first and only term, and has communicated that intent to Nebraska Gov. Dave Heineman.

Interesting, because Heineman is number one with a bullet in terms of Republican choices to replace him. Heineman has been a wildly popular vote-getter, so much so that he beat a true Nebraska legend'former congressman and Nebraska Cornhuskers head coach Tom Osborne, a man revered for bringing three national championships to Lincoln'in a 2006 gubernatorial primary, before crushing two hapless Democrats in the 2006 and 2010 general elections with over 73 percent of the vote in both cycles.

Will Heineman run? He passed up a shot at the Senate in 2012, so maybe he's not that interested, and he's not exactly a kid (he'll be 66 years old in 2014). True, 2014 may be an easier race'the Democratic field will be weaker this time out without former Sen. Bob Kerrey running'but Heineman is sufficiently popular that he doesn't really have to worry about who the Democratic nominee is, and never did; he'd have skated in 2012, and he'll skate now, if he wants the seat.

If he doesn't run, Reps. Jeff Fortenberry and Adrian Smith might seek to succeed Johanns, as might State Treasurer Don Stenberg (who has now run four times for the United States Senate, so who would put it past him?) Of course, in a truly open primary it's hard to know who might be competitive; current Sen. Deb Fischer, after all, was a little-known state senator two years ago but managed to win a wild three-way Republican primary.

On the Democratic side, Bob Kerrey is out, which pretty much leaves the number of well-known, well-funded Democrats on the bench at zero. There are, of course, a number of enterprising Nebraska Democrats looking at a statewide race, but chances are, most of them will opt for a potentially winnable gubernatorial race (Heineman is term-limited) rather than a suicide mission against Dave Heineman.

There is, of course, one Nebraskan who could conceivably run as a Democrat and win'a conservative with success in the private sector and a long record of service in Vietnam, in the Reagan administration, and two terms in the U.S. Senate, including a 2002 reelection bid when he won 81 percent of the vote.

That's Chuck Hagel, and perhaps Senate Republicans should think twice about blocking his nomination for secretary of defense.

3:48 PM PT (David Jarman): As for whether Heineman actually will run, we won't know right away; Heineman says he will take "a few days" to mull it over, though he did add a postscript to that, that he has never "indicated that being in the Senate is my dream job." Rep. Jeff Fortenberry also floated his name, saying "I will consider a run for the United States Senate" (though I suspect Fortenberry wouldn't get in if Heineman entered, since Fortenberry would have to give up his lifetime sinecure in NE-01 for a long-shot primary battle).

Roll Call also points out a few other GOP possibilities, in addition to the above-mentioned Heineman, Fortenberry, Smith, and Stenberg: one is ex-state Treasurer (and ex-naval aviator) Shane Osborn; another is businessman Pete Ricketts, who lost the 2006 Senate election to Ben Nelson (and son of Super PAC-funding, Cubs-owning Joe Ricketts). AG Jon Bruning is another possibility, though he still carries baggage from his 2012 GOP Senate primary loss to Fischer. Finally, they mention Nebraska's other Rep., NE-02's Lee Terry, who gave Politico the rather vague promise that "I will think about it at some time."