Joe Biden is fighting to save Social Security according to the liberal consensus from 1996. That's the problem.

On Wednesday, Bloomberg reporters came up with a fine piece of gotcha-journalism when they revealed that in 1996,  then-Representative Bernie Sanders said that Social Security had “been adjusted before, and adjustments will have to be made again.”

The quote emerged as the Sanders campaign was hitting former Vice President Joe Biden for calling for "adjustments" to Social Security--an attack that drew blowback as they had falsely painted Biden as praising then-Speaker Paul Ryan when Biden was in fact criticizing the Republican with a reputation as a wonk.

All of this has devolved into a fight over just what "adjustments" mean, and both campaigns--and their supporters--are exchanging plenty of accusations of bad faith. But with apologies in advance for attempting to add nuance to a primary campaign, both sides have a valid point with respect to the underlying argument, and, in my view, everyone's overlooking what this episode says about Biden's fundamental weaknesses as a candidate.

The context, which younger readers may not be familiar with, matters a lot. From early in Bill Clinton's Second term through the mid-aughts, "reforming" Social Security was among the hottest debates in the country. (It continues to this day, but after George W. Bush campaigned on partially privatizing the program in 2005 and got walloped in the 2006 midterms, "entitlement reform" lost quite a bit of momentum.)

The entire debate was framed, dishonestly, by deficit hawks in both parties. Conservative-leaning economists had successfully convinced the mainstream press and the larger public that the Social Security program was facing a looming crisis, and that if something wasn't done to stabilize its finances future retirees would be deprived of the benefits they'd earned during their working years and left desperate and penniless.

As I explained back in 2010, when the issue re-emerged during Obama's attempt to strike a "grand bargain" with the GOP, this "crisis" was based on a pack of lies, but it was nonetheless widely accepted as fact. Even today, polls consistently find that significant majorities of younger people believe the program won't be there for them when they retire. In the 1990s and early aughts, accepting the premise that Social Security required adjustments was essentially a prerequisite for being taken seriously.

Returning to the definition of adjustments, there were a number of proposals for "fixing" the "crisis." Briefly, they included raising or eliminating the cap on payroll taxes, raising the payroll tax rate, gradually raising the retirement age, and either reducing annual cost of living adjustments to reduce future benefits across the board or adjusting them progressively so that higher earners would face bigger benefit cuts than those with lower incomes.

And then there was the big kahuna, pushed relentless by the GOP: Partially privatizing the program, ostensibly to get a higher rate of return on the trillions stashed in the Social Security Trust Fund. (Contrary to popular opinion, they are not worthless IOUs.).

The near-consensus among liberals was that the program must not be privatized--a gift to Wall Street that would significantly increase the risk to retirees--and that staving off that effort required a mix of revenue increases and at least modest reductions in future benefits. This is what Obama's National Commission on Fiscal Responsibility and Reform, AKA "Simpson-Bowles," proposed in 2011. (Biden, whose Chief of Staff helped craft that proposal, supported it; Sanders called it a "sham.")

So returning to the present, both camps have a point. Biden has indeed long favored cutting Social Security benefits because while the "adjustments" he endorsed featured some progressive measures like raising the cap on payroll taxes, they also included provisions that would reduce future retirees' checks. At the same time, his defenders are right that this was an effort to "save" Social Security from what was a very real threat of privatization.

So why do I think this episode exposes his weakness as a nominee? In a nutshell, it's because so much has changed between 1996, when Bernie Sanders said that some adjustments were necessary, and 2018, when Biden echoed that sentiment.

First, progressives and many mainstream Democrats have come to see the pernicious effect of letting center-right economic orthodoxy frame the terms of debates like this one. Prominent liberals like Paul Krugman blasted Simpson-Bowles in 2011 and 2012, and by 2013 most of the Democratic establishment was calling for, in the words of the Center for American Progress, "hit[ting] the rest button on the entire fiscal debate." The Democratic think-tank also urged Obama to stop offering "concessions without any promise whatsoever from the president’s political adversaries that they will reciprocate."

When Biden said that the Social Security "still needs adjustments" in that 2018 speech, it felt like a rote inclusion by a candidate whose political outlook was shaped during another era when progressives were wandering the desert and deficit hawks had so successfully set the terms of debate that claiming that benefits needed to be tweaked was the price of admission for being seen as a serious voice in the discussion. That's a past that many of us don't want to return to.

Another, more recent shift within the Democratic coalition is a growing understanding, after learning some hard lessons during the Obama years, that Republicans are not interested in good-faith negotiations that might lead to compromises. Biden has already been criticized as out of touch for expressing the belief that after Trump is defeated the fever will break and he would be able to work across the aisle with Republicans to get things done. For many on the broad left, that suggests a divorce from the realities of the modern conservative movement. If you look at the context of that 15-year debate over Social Security, "making adjustments" implies striking a grand bargain that trims benefits and raises revenues, and the latter is simply a non-starter with today's GOP.

Joe Biden's defenders are right that he is a fundamentally decent person who has "fought for the middle class" as doing so has long been defined. But what this primary spat reveals is that he's essentially a time-traveler from the past who is out of touch with paradigm-changing shifts in both major parties and doesn't fully grasp the nature of the political conflicts in which we're engaged today.