The Sen. Bernie Sanders rally that I attended on the evening before the New Hampshire primary drew a reported 7,500 people — about twice as many as his actual 3,867-vote margin of victory in the primary the next day. I say that not to endorse crowd sizes as an alternative to the polls. (Despite the large crowds, Sanders slightly underperformed his polls in New Hampshire, in fact. ) Nor do I mean to imply that Sanders won in New Hampshire because of the rally. (It was held before a largely student audience at the University of New Hampshire — people who were already likely to vote for Sanders.) But it does go to show how razor-thin the margins have been so far in the primaries. The voters who pushed Sanders past former South Bend, Indiana, Mayor Pete Buttigieg in New Hampshire might only halfway fill a college hockey rink.

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But the rally was also impressive. It was full of star power, including speakers like Rep. Alexandria Ocasio-Cortez, former Ohio state Sen. Nina Turner, actress Cynthia Nixon and political activist Cornel West — all of whom were introduced to the crowd like heavyweight boxers — along with a concert by The Strokes. In between the big names, Sanders organizers gave students detailed voting instructions. Everything was tightly scripted. It was a show of force.

What the rally largely lacked, though, were attempts to persuade voters who weren’t already aboard the Sanders train. On the contrary, the emphasis was on turning out the faithful, and the faithful were all presumed to be on board with Sanders’s lefty platform. Nixon, for instance — who earlier had drawn a round of boos for a brief reference to Hillary Clinton, which she quickly shushed — said that nominating a moderate candidate would ensure that nobody showed up on Election Day.

But moderates were once a source of strength for Sanders. Four years ago, Sanders won voters who identified as moderate by 20 points in New Hampshire, about the same as his overall margin of victory in the state over Clinton. This time around, Sanders finished third among moderate voters, getting 16 percent of the moderate vote compared with 27 percent for both Buttigieg and Sen. Amy Klobuchar.

So, let’s talk about the “c” word: ceiling.

Does Sanders’s support have a ceiling?

I shudder to ask the question in part because of bad memories from four years ago, when theories about Donald Trump’s ceiling were a big reason that people like me initially dismissed his chances in the primaries.

In Trump’s case, though, there was at least some polling-driven evidence of a ceiling. He tended to lose ground in polls that asked about hypothetical head-to-head matchups against other Republicans, for instance. And his favorability ratings among Republican voters were quite low for someone who was leading the field.

There isn’t much evidence of this for Sanders. His favorability ratings are roughly as good as any other Democrat’s — and often the best in the field, depending on which poll you look at.

It’s also worth mentioning that Sanders gets a lot of support from younger African Americans and Hispanics, making his coalition among the most diverse in the race. Granted, he does have very little support from voters over the age of 65, but of all demographic deficiencies, that may be one of the easier ones to overcome. There are plenty of young voters in every state, provided you can turn them out.

Additionally, a set of YouGov polls last week showed Sanders winning in hypothetical head-to-head matchups against every other Democrat — narrowly beating former Vice President Joe Biden and Sen. Elizabeth Warren while more clearly defeating Buttigieg, Klobuchar and former New York Mayor Michael Bloomberg. (There are some qualifications to that YouGov poll: Buttigieg and Klobuchar still have fairly low name recognition, and earlier polling that tested head-to-head matchups hadn’t shown Sanders doing so well, especially against Biden.)

But if you look at the actual behavior of voters in Iowa and New Hampshire — and the most recent polling on how voters in the next states to vote are reacting to the Iowa and New Hampshire results — there are a few troubling signs for Sanders, including some evidence of what you might call a ceiling. In no particular order:

So overall, while Democratic turnout has been just fine, it has not exactly been revolutionary. It may even be that the Sanders campaign — if it has a highly loyal but relatively fixed number of voters — prefers lower turnout overall, since that means its base will make up a higher share of the electorate. In Iowa, with its relatively low turnout, 24 percent of voters were under 30. In New Hampshire, meanwhile, voters under 30 accounted for just 13 percent of the electorate, down from 19 percent in 2016.

Think less about ceilings, more about volatility

Over the course of building our primary model late last year, I grew less skeptical of Sanders’s chances. In fact, our model is now quite bullish on Sanders, having him as by far the most likely Democrat to win a majority of pledged delegates — although the most likely scenario is that no one wins a majority (meaning a contested convention is possible).

Ideally, working on a model helps you to see a race with a fresh set of eyes and reexamine premises that might be outdated. Relevant to Sanders, we found that endorsements had less predictive power than they had once had, no doubt in part because adding data from 2016 (when Trump won the GOP primary and Sanders was competitive against Clinton despite receiving little support from party insiders) undermined the “Party Decides” theory of the race. Conversely, we found that fundraising was more predictive than we had previously assumed.

I don’t want to go overboard here: The media probably still overstates the importance of money overall, and for the most part, the best indicator of a candidate’s position in the race is simply his or her polls. Nonetheless, Sanders’s lack of endorsements is only a marginal reason to be worried about his chances, while his excellent small-donor fundraising is a reason to be optimistic.

We also found in building the model that the concept of “ceilings” and “floors” tends to be rather fuzzy; like “electability,” it’s something that would benefit from more precise specification. For instance, we found no evidence that candidates who were frequently cited in polls as voters’ second-choice picks were more likely to increase their support than ones who weren’t. (Although that data is hard to come by for previous election cycles, so I wouldn’t take that conclusion as definitive.)

But we did find that for candidates who carved out their own space and had few close substitutes, the polling behaved differently than it did for those who had a lot of competition.

To categorize candidates, we rate them along four dimensions:

How liberal or moderate they are on social policy.

How leftist or centrist they are on economic policy.

Whether they portray themselves as “insiders” or “outsiders.”

Whether they tend to be technocrats (who mostly appeal to elites and college-educated voters) or populists (who mostly draw support from the working class).

And in this conception, Sanders is something of an island unto himself. Warren is close to him on the issues, but she is less anti-establishment and more reliant on support from college-educated voters than he is. None of the other major candidates are very close to Sanders at all.

This means someone like Sanders has few direct competitors, so his polling swings tend to be smaller. If things are going poorly, there are fewer places for his voters to go because there isn’t a clear alternative to him. But someone like Sanders also tends to pick up less support from other candidates when things are going well because he’d represent a big leap for, say, a college-educated, moderate Klobuchar supporter.

Conversely, a candidate like Buttigieg — or Sen. Kamala Harris, before she quit the race — can experience more polling booms and busts. In trying to be an acceptable choice to everyone, these candidates have high upside potential, but because they may be relatively few voters’ first choice, they can also have a low floor.

To put it another way, instead of thinking of hard ceilings, it’s probably best to think of candidates as being either low or high volatility based on the amount of competition they face. It’s also best to think of this as being a dynamic status that can evolve over the course of the race. For example, Biden once seemed to have little direct competition, but the growth in support for Bloomberg, Buttigieg and Klobuchar has suddenly made the moderate/establishment lane far more crowded.

As to whether you’d prefer to be a low-volatility or high-volatility candidate, that depends on a lot of factors. But being a low-volatility candidate definitely helped Sanders during a rough stretch of the campaign in early October when Warren was surging in the polls and he took a break from the trail following a heart attack.

At the time, I thought some of his supporters would jump ship to Warren, perhaps putting her in the overall driver’s seat for the nomination. Instead, Sanders’s base largely stuck with him, and he received endorsements from Ocasio-Cortez and others. And by late November, Sanders had overtaken Warren and reclaimed second place in national polls. It was an impressive show of loyalty from his supporters.

So even if you do want to think in terms of ceilings instead of volatility, know that ceilings imply the existence of floors — and low ceilings and high floors generally go together. Having a high floor can be helpful, too, especially in a multicandidate race where the support of 20 or 25 percent of voters can be enough to lead polls and win states.

Sanders has several ways to win

To state the obvious, no one knows with much certainty how the Democratic race is going to turn out. But Sanders will likely have some paths to victory available almost no matter what:

If everything stays the same, Sanders could win the nomination with a plurality of pledged delegates. It remains quite possible that some candidate — whether it’s Sanders or someone else — will have some kind of polling surge in the race soon, making the top of the field less crowded. But suppose that doesn’t happen and the race muddles along roughly as it is now, with Sanders at around 25 percent of the vote and several moderate candidates with around 15 percent each.

That would actually be a pretty nice scenario for Sanders. He’d get delegates almost everywhere, whereas the moderate candidates sometimes wouldn’t, depending on whether they hit the threshold required to win delegates in each state and district. So you could go into the convention with a scenario like: Sanders has 40 percent of pledged delegates, one of the moderates (Biden, Bloomberg, Buttigieg or Klobuchar) has 30 percent, while another moderate candidate has 25 percent, and Warren has 5 percent.

Would convention delegates try to deny Sanders the nomination when he had a fairly clear plurality? I don’t know. (Our forecast model doesn’t try to predict the outcome of a contested convention.) It would be a heck of a story to cover. Sanders certainly would have a decent shot, though. And if Sanders had a very clear plurality — say, 47 percent of the delegates, while the next-closest competitor had 28 percent — his chances would be stronger still.

As the rest of the field slowly consolidates, Sanders could gradually increase his vote share just enough to win a narrow majority. Even if the moderate lane narrowed to just one or two alternatives later on in the race — say, at some point in March or April — Sanders would still be in a pretty decent position. He would probably have a head start on the competition by having won a lot of delegates on Super Tuesday and in the first four states while the rest of the field sorted itself out. Contests up to and including Super Tuesday account for 38 percent of all pledged delegates, so this matters a lot.

Also, even if there is some upward resistance to Sanders’s numbers — more than there might be for the average candidate — it isn’t likely to be absolute resistance. Case in point: Sanders improved his support from 15 percent in national polls for much of last year to the low-to-mid 20s now. Without those gains, Sanders might be in the fairly difficult position that Warren now finds herself in, following third- or fourth-place finishes in Iowa and New Hampshire.

Making slow-but-steady polling gains was roughly the path that Trump followed in 2016 to win the Republican nomination, too. True, Trump had one major advantage that Sanders didn’t: the presence of winner-take-all states, especially later on in the race. (All Democratic states use proportional delegate allocation for candidates who clear the 15 percent threshold for getting any delegates.) Still, Trump gained ground later in the race once Republican voters realized that they faced a choice between Trump and a contested convention (which might nonetheless have resulted in his nomination). Democratic voters might act similarly. Maybe a voter would prefer Buttigieg to Sanders in the abstract, but if a Buttigieg win would require a contested convention while a Sanders win would not, she might feel differently.

Sanders could easily win a one-on-one race. Finally, suppose that we do wind up with a two-candidate race fairly soon; Biden loses South Carolina, for instance, and quits the race, and the large majority of delegates on Super Tuesday go to either Sanders or Bloomberg.

This seems to be the outcome that a lot of moderates I talk to are rooting for, but it could also fairly easily lead to a Sanders nomination. If Sanders’s main opponent was Bloomberg, for instance, he’d play perfectly into Sanders’s messaging about the corrosive influence of money on the democratic process. Bloomberg also has a lot of baggage that has been somewhat unscrutinized because of his late entry into the race. Against Buttigieg or Klobuchar, meanwhile, Sanders would probably have the more diverse coalition, and he’d also have an organizational advantage against someone like Klobuchar, who is only now starting to raise serious money.

I don’t know who would be favored in a head-to-head matchup between Sanders and another Democratic candidate, especially a resilient Biden, or if it somehow came down to Sanders and Warren. (As the YouGov polling shows, these are potentially tougher matchups for Sanders.) But the bottom line is this: Even if Sanders is far from the textbook nominee — and even if he’s likely to have some trouble winning new voters to his side — all of the other candidates have a lot of problems too. Sanders is in the strongest position for now, and he has a high floor of support that should win him delegates almost everywhere, while the rest of the field is a mess behind him. Ceiling or not, that’s why you’d rather be in his position than anyone else’s.