And yet it’s worth trying to pop these trial balloons when they go up, as progressive outrage may have scuttled any cave-in on Medicare eligibility. Although people I respect, including Jared Bernstein at times, and for a moment, Paul Krugman, have suggested that the chained CPI deal is the least bad of all the bad ideas being floated as part of a fiscal cliff  “grand bargain,” it’s still a bad idea, for moral, political and policy reasons, and it’s worth fighting.

Such a deal makes a liar out of Vice President Joe Biden, who flat out promised on the campaign trail that there would be no Social Security cuts. Only a week ago, press secretary Jay Carney said the president wouldn’t put Social Security on the table because the program is self-funded and is not driving the deficit. Democrats, including Obama ally Sen. Dick Durbin, have been very clear on that message: keep Social Security out of deficit discussions, because it has nothing to do with the deficit. Sen. Majority Leader Harry Reid likewise promised Social Security would not be touched in the negotiations.

Now Carney is saying the opposite: “This is something that the Republicans have asked for and as part of an effort to find common ground with Republicans, the president has agreed to put this in his proposal,” replied Carney. “He has agreed to have this as part of a broad deficit reduction package.” So was Carney dissembling when he said it wasn’t contributing to the deficit? Why are Democrats stepping on their own message like that?

Even though administration negotiators are promising they’d soften the blow with help for the neediest seniors, let’s just lay out what the chained CPI would do as is. First of all, it amounts to a $56 a month benefit cut for the typical single elderly woman by age 80, according to the National Women’s Law Center. That’s “an amount equal to the cost of one week’s worth of food each month,” the center observes (h/t the Nation). Remember when Democrats were the party of women? Oh, that’s so last month.

Even some Democrats like to depict Social Security recipients as greedy geezers living well while the younger generation struggles. So it’s worth remembering: almost 70 percent depend on Social Security for more than half of their income; for 40 percent, it’s more than 90 percent of their income. And average benefits are less than $15,000 a year. This is because incomes have stagnated but also, pensions have gone the way of the VCR. After decades of declining, poverty rates for seniors are now climbing. We should be expanding Social Security, not cutting it.

In the meantime, ignore the posturing on Boehner’s so-called Plan B, which is DOA.  (I said that on MSNBC’s “The Ed Show” last night; what matters more is Robert Costa said it in the National Review today.) It’s a craven attempt to seem reasonable about taxes while remaining the lap dogs of the rich. Arizona Republican Sen. Jeff Flake backs it because “we would only get serious talk on spending cuts once we aren’t considered the party of the 2 percent,” he said. Sorry, Senator, you will be the party of the 2 percent no matter what happens on Plan B. It may not pass the House, anyway: It wouldn’t be the first time Boehner didn’t have the votes in his caucus he thought he did. Last time it happened, on the vote to cut spending and keep the government running, Minority Leader Nancy Pelosi had to whip reluctant Democrats into voting for the budget-cutting “compromise.” Pelosi won’t do that this time.

Will she do it for a “grand bargain” that includes the chained CPI? She seemed to say she would in an interview with MSNBC’s Andrea Mitchell Tuesday.  But other liberal Democrats, including Sens. Durbin, Sherrod Brown, Jeff Merkley and Bernie Sanders, plus longtime Obama supporters Jan Schakowsky, Keith Ellison and Donna Edwards in the House, are promising to fight the move. It will be fascinating to see where Pelosi lands on the issue.

It has to be acknowledged that the White House is willing to make painful concessions because Obama’s proposed deal does some very good things, as Alex Seitz-Wald explains: it extends unemployment benefits as well as earlier expansions to the earned income tax credit and the child tax credit. If those credits go away, low-income working parents will lose as much as $1,000 annually. It’s theoretically possible the president will negotiate such a superb package of tax hikes on the rich plus extended tax credits plus infrastructure spending that a minor tweak to the way benefits are raised is a reasonable sacrifice. But I find it hard to imagine those good things will remain in a final deal that also cushions the chained-CPI blow to seniors.

Paul Krugman, who went from “marginally positive to marginally negative” on a potential deal, now seems to be flat-out opposed, based on reports that the White House continues to compromise on tax rates, including on dividend income. (Again, the operative word is “reports”; we know nothing concrete.) “All of a sudden it’s feeling a lot like 2011 again, with the president negotiating with himself while the other side enjoys the process,” Krugman wrote this morning. “So Obama needs to draw a line right now: no further concessions. None. He’s already given too much.

“Yes, this probably means going over the cliff,” Krugman says. “So be it: it’s less bad than the alternative.”

It’s hard not to notice that the president’s approval numbers climbed after he began standing up to Republicans at the end of 2011; they’ve climbed higher still since the election, when – until this week – he stood firmly behind ending the Bush tax cuts for those making $250,000 and above, and seemed to oppose benefit cuts for Social Security and Medicare (I have to say “seemed to,” because to be fair, he’s always used weaselly wording that left him wiggle room.) Right now his approval ratings are higher than they’ve been since the week he announced the killing of Osama bin Laden.

It’s likely the president thinks that political capital will let him sell a compromise to the American people, even though polls show they strongly oppose cuts to Social Security. In Michael Scherer’s Time profile of its Man of the Year, he quotes an Obama adviser who kicked off the 2012 campaign with intensive focus groups among swing-state voters. He reported back to Chicago: “Here is the best thing: People trust him.”

No doubt the president and his people think that translates into “people trust him, and therefore they’ll trust this deal is the best he could do.” Maybe they’re right. But it’s also possible that months of promising to protect Social Security, and weeks of saying it shouldn’t be part of a fiscal-cliff deal because it doesn’t increase the deficit, will leave Americans wondering what the truth is, and who they should believe. I worry about what happens when Democrats say they stand for one thing, but do another.

In the end, as he was in 2011, Obama may be saved from having to make good on his promises because of the intransigence of Republicans.  As I write, far-right House members are going increasingly crazy about Boehner’s Plan B “compromise,” and it’s possible he won’t stand up to them. But it would be great to see what would happen if Democrats did.

Update: It looks like Democrats are going to have to stand up to Boehner, because at what BuzzFeed is calling “the shortest press conference ever”, the besieged House Speaker simply told reporters: “The president will have a decision to make.”   Indeed.