If polling is to be believed, Joe Biden is now far and away the frontrunner for the 2020 Democratic nomination. The question is whether that can last now that the target is squarely on his back.

There is a clear appetite among some Democrats to coalesce around Biden and avoid a food fight. But there is also rising animus toward Biden on the left, and no hesitation from Bernie Sanders and Elizabeth Warren to take him on.

If t hey draw blood, we're going to have a messier scrum. And with 20 candidates all vying for the top spot, things could get out of control. That’s because a large field breeds chaos and uncertainty.

Complicating matters is this: Even though at present Democratic voters seem to be embracing pragmatism, Democrats’ proportional voting (as opposed to winner-take-all states) could slow down the winnowing process and possibly breed a convention fight.

It’s really hard to come out of a long process like that poised to defeat an incumbent.

Trust me, as a center-right columnist, I watched Donald Trump hijack the Republican nomination in 2016. And four years earlier, I watched the GOP fall prey to the same collective action problem, which resulted in a clown car primary.

Back then, l embraced a sort of Hayekian theory that competition was an unmitigated good. The more primary candidates, I reasoned, the merrier. Let there be a competition of ideas! Spontaneous order would take care of everything.

Yeah, not so much.

One thing I learned is that once an unwieldy campaign is allowed to metastasize, people begin behaving in unpredictable ways.

In 2016, Ted Cruz’s campaign actually helped Donald Trump win New Hampshire, which was vital to his winning the nomination.

Why would Cruz help the guy he just narrowly beat in Iowa? As Politico’s Shane Goldmacher explained, “… that’s part of the complex, multidimensional chess match that was the Republican primary, a contest which still featured a dozen GOP candidates at that time.” The plan was to get Trump one-on-one, where (of course) Cruz would emerge the winner.

Obviously, helping Trump turned out to be a colossal error for Cruz (thanks, Ted!), but consider the other assists Trump had on his way to the nomination. Chris Christie turned himself into a virtual suicide bomber to take down Marco Rubio just before the New Hampshire primary―just as Jeb Bush’s Super PAC spent a fortune destroying Rubio, while viewing Trump as “frankly, other people's problem.”

Now, Democrats don’t appear to be as petulant as Ted Cruz—although, if you think about it, I doubt if stories about Amy Klobuchar eating a salad with a comb just materialized organically, just as stories about Joe Biden making a Nevada candidate “feel” uneasy don’t just happen to drop right before he announces his run for president.

Already, the number of candidates jockeying for position is impacting the race. Consider how Democrats are currently engaging in a game of stupid human tricks. Already, the large field has distorted the campaign, causing candidates to focus on making it to the debate stage instead of building campaign infrastructure in key states.

“ This race could get really ugly really fast. ”

It may look like this is all a fun side show and that Joe Biden is invincible. But remember, this race is dynamic, not static or linear. Sometimes the wheels come off. And sometimes, they come off as a result of sabotage.

Who knows how this could manifest (maybe Bernie tries to help Kamala win South Carolina, thereby depriving Biden of electoral votes). It could be that the proportional voting makes it less likely that Democrats will help throw a state to an adversary. But politics does make strange bedfellows.

The good news for Democrats is that they don’t appear to have any candidates who are in what we might consider Donald Trump (or even Ben Carson) territory, meaning that—even if this race spirals out of control—they’re not likely to nominate a fringe candidate (unless you consider Sanders a fringe candidate—which is open to debate). The Alexandria Ocasio-Cortezes and Ilhan Omars of the party are (thankfully for Democrats) not running. (AOC is too young.) And so, the potential downside of nominating the wrong person isn’t as great as it might otherwise be.

Still, the longer a campaign goes on, the stranger things can get. For example, in 2012, conservatives Michele Bachmann and Ron Paul both teamed up to help Mitt Romney win the GOP nomination. In one debate, Bachmann attacked Rick Perry over mandatory HPV vaccinations (she went on to endorse Romney). Likewise, Ron Paul attacked Rick Perry during the debates, while buddying up to Mitt Romney. Philosophically speaking, this doesn’t make much sense, unless you understand that they each viewed the more conservative Perry as a bigger threat to their turf.

With the Democratic debates just around the corner, this is the kind of thing to keep an eye on.

The biggest factor in whether Democrats can defeat Donald Trump is probably as simple as who they nominate. Having said that, a close second may well be how quickly they settle on that nominee.

This race could get really ugly really fast.