The tragedy of the commons and vote-splitters losing to Bernie Sanders

Now that Bernie Sanders has won 2 of the first 3 states (Pete Buttigieg seems to have narrowly won in Iowa's delegates, but the results are still being disputes), we're seeing reports like this:

The basic logic has never been in question: If Joe Biden, Michael Bloomberg, Pete Buttigieg, Elizabeth Warren, Amy Klobuchar, and Tom Steyer all stayed in the race, they would continue splitting the delegates needed for the nomination while Sanders built up a commanding plurality.

Many of the candidates themselves agreed, and had started saying so in recent days. Some Bloomberg aides have called hosts of recent Biden fundraising events to dress them down for effectively boosting Sanders, according to Democrats familiar with the conversations.

And before last week’s debate, a Bloomberg campaign memo warned, “If Biden, Buttigieg, and Klobuchar remain in the race despite having no path to appreciably collecting delegates on Super Tuesday (and beyond), they will propel Sanders to a seemingly insurmountable delegate lead.”

The next day, Buttigieg’s team shot back a warning that Bloomberg “will propel Sanders to a seemingly insurmountable delegate lead,” and then, later that day, Warren’s top surrogate, Julián Castro, called on Bloomberg to “drop out now,” too.

But the day after a decisive Sanders victory in Nevada, his rivals are all intent on staying in. Given the general agreement among anti-Sanders moderates that the field needs to shrink, why won’t anyone drop out?

To start, none of the candidates want to get out before any of their peers, if they can still conceive of some sliver of a path to victory.… [E]ach camp acknowledges that the party isn’t split into clear pro- and anti-Sanders lanes like many pundits imagine. After all, the Vermont senator is widely popular in the party, so he would likely continue to pick up a substantial share of support from any candidates who stepped aside.

Still, all the campaigns are convinced they are the one that’s best positioned to take on Sanders one-on-one. Some of the Biden donors, for example, told the Bloomberg aides calling to scold them that the former mayor is hardly one to talk if he’s accusing Biden of helping Sanders.

Beyond all this, there’s no organized effort to shrink the field, and none is coming.

“People have this idea — and Sanders stokes this — that there’s a Democratic establishment that’s meeting and figuring these things out. [The truth is] there’s a bunch of people who have different interests,” one top party operative explained after Sanders’s wide margin of victory in Nevada became clear.…

Klobuchar, for one, has been the subject of hushed speculation that she’s aiming to win enough delegates in upcoming contests in her home state of Minnesota and neighbors like North Dakota to be influential at the convention. But in Fargo on Sunday, she insisted she’s still trying to win, comparing her campaign to Bill Clinton’s, which also didn’t win any statewide contests until Super Tuesday.

Warren, meanwhile, has been trying to position herself as a Sanders alternative by becoming the field’s foremost Bloomberg attacker, even as a disappointing result in Nevada makes her road to victory look especially daunting.

Biden, too, has a tough path ahead, but is convinced a clear win in South Carolina could set him up as the non-Sanders portion of the party’s best bet.

And Buttigieg, who effectively tied Sanders in Iowa and came in second in New Hampshire, is using those results and his recent attacks on Sanders to claim that he is the obvious choice. “Pete has shown he’s the only candidate who can beat Sanders. In the first two contests so far, Pete is the only candidate who provides any real competition,” read his campaign’s postdebate (but pre-Nevada caucus) memo.

If any one candidate is facing the pressure more than the others, though, it’s Steyer. The California billionaire has yet to win a delegate, but he’s polling in third in South Carolina on the back of his massive investments (of money and time) there. Steyer’s critics argue that he has no shot at winning the nomination, and that his double-digit support in the state must be keeping Biden’s down. If he were to drop out, their theory goes, Biden might win the next primary by a comfortable margin instead of wrestling for it with Sanders.

Steyer, though, has consistently dismissed this idea.…

“People are lying now about their ability to win, what they’re actually in the race for. If people keep lying for the next nine days, we’re going to end up in a position where Sanders is probably going to be the nominee by default. And people are going to say, ‘What happened?,’” [a Democratic strategist said]. “You were faking it for all of February. That’s what happened.”

Wikipedia says this on "the tragedy of the commons":

The tragedy of the commons is a situation in a shared-resource system where individual users, acting independently according to their own self-interest, behave contrary to the common good of all users by depleting or spoiling the shared resource through their collective action.…

The "tragedy of the commons" is often cited in connection with sustainable development, meshing economic growth and environmental protection.… It has also been used in analyzing behavior in the fields of economics, evolutionary psychology, anthropology, game theory, politics, taxation and sociology.…

The commons dilemma is a specific class of social dilemma in which people's short-term selfish interests are at odds with long-term group interests and the common good.[35] In academia, a range of related terminology has also been used as shorthand for the theory or aspects of it, including resource dilemma, take-some dilemma, and common pool resource.

ADDED: A reader questioned whether this is really a tragedy of the commons problem, since only one of the Democratic candidates can end up winning the nomination. I responded on Facebook:

If you define "tragedy of the commons" so strictly that it applies only where every single person in the system is demonstrably worse off, then it's an open question whether there's a tragedy of the commons going on here. For instance, Klobuchar could be worse off for staying in and causing the nomination to go to Sanders. Sanders is unlikely to pick Klobuchar as a running mate or for any other position. If Klobuchar dropped out today and caused Buttigieg to win the nomination, that could be better for Klobuchar, since Buttigieg would be more likely than Sanders to choose Klobuchar as a running mate or for something else (their occasional tiffs would be more easily smoothed over than the epic Obama vs. Clinton battle of 2008, which didn't stop Obama from choosing Clinton as Secretary of State). If Klobuchar could become Vice President at age 60, she'd become more likely to end up being president than if she just stays in the Senate.

If instead you use a somewhat flexible definition of "tragedy of the commons," it very much applies to this situation. There are millions of Democrats involved with this in one way or another. There's no way to prove that every one of them who isn't named Sanders is going to be worse off if the other candidates keep splitting the vote. But if we look more broadly at whether it'll be good for Democrats in general, we can see a tragedy of the commons dynamic in the way Buttigieg/Bloomberg/Biden/Klobuchar/Steyer keep pursuing their individual interest in keeping their campaigns going in a way that collectively reduces the chances of a Democrat replacing Trump in January.