Folks, if you're not watching the South Carolina debate, you really should tune in.

I can't take notes quickly enough to keep up, so here's a paraphrased run-down of what's just transpired on the second question...

OBAMA: Hillary Clinton has been distorting my record -- including what I said about Ronald Reagan in an editorial board meeting, suggesting I praised Republican ideas.

CLINTON:  I'm just going by what you've said.  You said the Republicans were the party of ideas and that you admired them for it.

OBAMA:  I never said that.

CLINTON:  Yes you did.

OBAMA:  No, I didn't.  I said he was a transformative figure.  I've always disagreed with his ideas.  I saw the impact they had on communities during the 1980s, because I was organizing on the streets of Chicago back then -- while you were a corporate laywer sitting on the board of Wal-Mart.

CLINTON:  Let's get back to the quote. 

And then, later, Clinton denied making a certain accusation about Obama, saying this:

CLINTON:  I didn't say that.

OBAMA:  OK, your husband did.

CLINTON:  Well, he's not here now -- I am.

OBAMA.  I know, but sometimes it's hard to know who I am running against.

At that point, Clinton said something about Obama working for a slum lord -- frankly, I couldn't hear because my wife and I were too busy gasping at the back and forth.  Then Edwards spoke, suggesting that this wasn't helpilng to get people jobs and make sure kids have health insurance -- and that, by the way, he was the first candidate with comprehensive plans for universal health care, energy, and such.  (All true claims, as best as I can tell.)

I'll revisit this all when I have a real transcript -- and maybe video.  In the meantime, I think it's safe to say that Obama has decided he's going to hit back at Clinton -- and the Clintons -- in this debate.  And it's become something of a free-for-all.

Note: notwithstanding this exchange, it's actually been quite substantive.  Prior to this, there was a very meaty debate about trade. 

Update: Marc Ambinder has some of the precise excerpts.

Update 2: Ben Smith has a longer transcript

--Jonathan Cohn