WHAT BAYH IS THINKING…. Sen. Evan Bayh’s (D-Ind.) retirement is a shocker, leading many to wonder what on earth a popular incumbent with plenty of money and a big lead in the polls is thinking. Bayh alluded to his frustrations on the Hill as part of his rationale.

“Two weeks ago, the Senate voted down a bipartisan commission to deal with one of the greatest threats facing our nation: our exploding deficits and debt. The measure would have passed, but seven members who had endorsed the idea instead voted ‘no’ for short-term political reasons,” he said. “Just last week, a major piece of legislation to create jobs — the public’s top priority — fell apart amid complaints from both the left and right. All of this and much more has led me to believe that there are better ways to serve my fellow citizens, my beloved state4 [sic] and our nation than continued service in Congress.”

This sounds a bit like Bill Bradley’s rationale in 1996 — politics on Capitol Hill has become ugly and difficult, so I’m walking away.

But it’s not exactly a compelling explanation. To hear Evan Bayh tell it, Republicans have made it impossible for Congress to work on issues important to him … so he’s decided to make it easier for the Republican caucus to have more power.

When the going gets tough, the conserva-Dems pack up and go home?

What’s more, while I’m hardly familiar with Indiana’s election procedures, reliable sources report that the filing deadline for candidates interested in the Senate race is this week, meaning Dems will have to scramble. If these reports are accurate, it would appear Bayh is hurting Democrats twice — once by walking away when they need his vote, and again by making it extremely difficult for the party to find, recruit, and qualify a top-tier candidate to run in his stead.

For what it’s worth, a great deal of the early talk — and by “early,” I mean “the last hour” — is about the DSCC recruiting Rep. Brad Ellsworth (D), a Blue Dog and former county police sheriff from Indiana’s Southwest corner.

Stay tuned.

Update: It appears that the signatures for a prospective candidate are due tomorrow, and it’s extremely unlikely any Dem could pull this off in time. What’s more likely, then, is that the Indiana Democratic Party will be responsible for selecting a candidate — there would be no primary.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.