Was it Professor Graham, in the immigration hall, with a rope?  Or perhaps it was Colonel Kerry in the climate-change study, with a lead pipe?  Investors Business Daily says it was actually Mr. Reid, in the back room, with a heavy stack of paper and a laser focus on survival:

The climate change bill isn’t even officially dead (in fact, it was never officially resurrected),  but that hasn’t stopped a lot of finger-pointing over who is responsible. Democrats and their allies are pointing their fingers at Sen. Lindsey Graham, R-S.C., one of the co-authors of the bill, because he walked away late Friday. But is that fair? Not really; the fix appeared to be in well before that. Graham, it seems, was just acknowledging that it was already a goner.

Early last week, the bill’s co-authors John Kerry, D-Mass., and Joe Lieberman, D-Conn., told reporters, including this one, that they had a deal with the Senate leadership to move forward with the legislation on Monday, April 26.

The three would unveil the legislation and Senate Majority Leader Harry Reid, D-Nev., would personally manage it. This would maximize the odds that despite the limited time left on the schedule — the Senate still has to confirm a new Supreme Court justice, finish a budget and pass financial regulatory reform — that it would get done.

“We don’t want this to be introduced and then referred to committee. Senator Reid will take it, negotiate it and then bring it to the floor hopefully in June,” Lieberman said.

That was last Tuesday. The next day though, various reports started popping up in the press that Reid and the rest of the Democratic leadership were heading in a different direction.

Why?  What happened to the bill that had been the administration’s second-highest domestic agenda priority, just behind health care?  Harry Reid took a look at the polls in Nevada and decided he needed a Hail Mary:

Senate Majority Leader Harry Reid, trailing in polls in heavily Hispanic Nevada, wants to pursue legislation to provide legal status for many unlawful immigrants before the Senate tackles a climate change and energy bill and as Democrats defend their congressional majorities ahead of the November congressional elections.

Reid broached the change of priorities during a meeting this week with House Speaker Nancy Pelosi, according to two Democratic officials familiar with the developments.

It’s easy to miss how strange this mid-course correction actually is.  While Democrats may want to use immigration to split Republicans, it’s also likely to further endanger their own Blue Dogs in the House, who already will take the brunt of the anger from voters over ObamaCare and the moribund economy.  That wouldn’t happen with cap-and-trade, which has already passed the House once, although it will almost certainly come back again when the Senate changes the bill.

In contrast, an immigration bill hasn’t even yet been written.  The House and the Senate have to start from scratch and work their way through committees, giving the GOP plenty of opportunities to highlight amnesty or amnesty-lite positions.  It will take weeks, and more likely months, for a bill to push through to a successful conclusion, assuming one is possible in a midterm election year.  The effort will do considerable damage to Democrats and make cap-and-trade nothing more than a wistful memory, since the next Congress will have to start that effort from Square One if nothing passes this year — assuming the next Congress takes it up at all.

Given that, why did Harry Reid push to switch the priorities?  He wants to pander to Latinos, which is about the only hope he has of winning re-election in Nevada.  If he pushes cap-and-trade and lets immigration reform languish, Reid won’t get enough support from Hispanic voters.  With this switch, Reid can at least claim that he tried to get something done, even if the end result is that neither bill passes or comes to a vote.

So whodunit?  Harry Reid and Nancy Pelosi … likely with the White House as an accomplice.

Update: Allahpundit will likely have more on this later, but Lindsey Graham now says no immigration bill until 2012 — the earliest he figures the borders can be properly secured.