At TimesWatch sister site NewsBusters, Noel Sheppard  documented the fireworks as Times columnist Paul Krugman accused the press of not uncovering Mitt Romney's "flat-out untruths" on ABC's This Week show, then was accused of lying about Medicare by Republican strategist Mary Matalin.
Here's part of the exchange from Sunday's show.
PAUL KRUGMAN: But can -- I don't want to skip by without talking about the facts issue, because Romney...
GEORGE STEPHANOPOULOS, HOST: We have plenty of time coming up.
KRUGMAN: I don't know whether to blame [debate host Jim] Lehrer or blame the president but it was kind of amazing because Romney was not only saying things that are not true, he was saying things that his own campaign had previously said weren't true. The one that got me was not the stuff about taxes but the thing about covering people with pre-existing conditions which his plan does not, which he has said that before and his campaign has walked it back in the past and there he was right again saying, well, my plan covers people with pre-existing conditions which is displaying a kind of contempt to the public...
STEPHANOPOULOS: So you think it's the moderator's job to call him on that...
KRUGMAN: No, I'm not sure whose job it is, but it is -- there's a contempt for the whole process. There's a contempt for us people, because he's thinking the news media will not cover me on this, as long as they say it forcefully they'll say I won, which is more of the ways...
MARY MATALIN: Oh, you're going to say the press is against Obama now?
KRUGMAN: The press just doesn't know how to handle flat-out untruths.
Sheppard noted that Republican strategist Matalin later told Krugman, "You're hardly credible on calling somebody else a liar ." Here's that exchange:
PEGGY NOONAN, WALL STREET JOURNAL: Barack Obama was supposed to be this sort of moderate, centrist fellow who looked at Mitt Romney, this extreme, strange fellow. By the time that debate was over, Mitt Romney seemed a completely, moderate, centrist figure who showed up as Mitt Romney the governor, not as Mitt Romney the candidate.
KRUGMAN: Except that everything he used to claim his centrism wasn't true, so this is a question, does that start to take its toll over the next few months?
NOONAN: I just think that is unjust. I mean to say the very least --
KRUGMAN: When you say, “My plan covers pre-existing conditions,” when it doesn't, and when your own campaign has admitted in the past that it doesn't, what do you say? That's amazing.
MARY MATALIN: Professor, can I ask you? You have mischaracterized and you have lied about every position and every particular of the Ryan plan on Medicare, from the efficiency of Medicare administration to calling it a voucher plan. So you're hardly credible on calling somebody else a liar.
Matalin may have been thinking back to September 2011 , when Krugman said on CNN that Paul Ryan's Medicare plan "the voucher would kill people, no question."