Mystery Hold on Groves Nomination

ABC's Gary Langer reports that a mystery senator has put a "hold" on the nomination of Robert Groves:

Three weeks after Robert M. Groves sailed through his confirmation hearing to lead the U.S. Census Bureau, a Republican U.S. senator has placed the nomination on hold.

As for who and why, it's Mystery Hour at the U.S. Senate.

A Democratic staffer this afternoon suggested to our senior congressional correspondent Jonathan Karl that signs seemed to point to Sen. Robert Bennett, R-Utah. Nope: "It's not us," says Bennett's spokesman, Tara Hendershott. "We don't have a hold."

Someone clearly does. The majority leader, Sen. Harry Reid, D-Nev., asked this evening for unanimous consent to move the Groves nomination to a vote - and the minority leader, Sen. Mitch McConnell, R-Ky., objected.

For those who have not been following the story, Groves is a hugely respected figure within the survey research community (I interviewed him at the 2008 AAPOR conference).

If any of Pollster's very well informed readers has any tips as to which senator is behind the hold, please drop me a line.

Update - Congress Daily's Carrie Dann has more, including this:

One Democratic aide said the apparent hold on Groves' nomination is
not cause for concern, considering how quickly the confirmation vote
was brought to the Senate floor.

"Sudden movements make people nervous," said the aide. "Next week we'll know if there's a real problem or not."