This piece was originally published by FiveThirtyEight on Feb 25, 2020.

At this point in the Democratic primary, none of the moderate alternatives to Sen. Bernie Sanders has risen above the rest. Sanders has emerged from the first three voting contests as the race’s progressive front-runner, and voters who think Sanders is too liberal are still left with several choices.

It might seem like “moderate” voters could consolidate behind one alternative to thwart Sanders’s path to the nomination. That’s possible, but one thing it assumes is that voters understand politics in ideological terms. And many don’t — political scientists have long found that most of the public does not fit into neat ideological boxes.

Rather, people often hold conflicting opinions on policy issues. Fundamentally, many don’t think of politics as a battle between the left and the right. For instance, a voter could be pro-choice on the question of abortion and in favor of Obamacare, while also against increased gun control and raising taxes. Another voter might identify as a moderate and independent, even if they agree with Democrats on most policy issues. What’s more, either one of these two hypothetical voters could vote for President Trump simply because the economy is doing well, regardless of their other political beliefs.

There is some evidence that Americans are becoming more ideologically divided, but there is still a pretty big gap between rank-and-file voters and elected officials and party leaders. Where voters do match the views of their party leaders, it is often because some people are changing their views on issues like race and gender to better match their party leaders.

We can’t use ideology, by itself, to perfectly predict which candidates voters will rally behind as the field winnows. Which is why even if one moderate alternative were to emerge to Sanders, it doesn’t necessarily mean that candidate would benefit — Sanders could gain, too.

Ideology-driven politics is slowly on the rise

Until recently, ideology played a limited role in American public opinion because the parties themselves were not that distinguishable on matters of ideology. In 1956, Americans could identify the party nominees’ positions on an issue and had a position on it themselves only 31 percent of the time. But by 2012 that number had risen to 77 percent. Likewise, the percentage of Americans that said they saw important differences between the parties rose, from 50 percent in 1952 to 83 percent in 2016.

So Americans are becoming more ideologically aware and as such, recognize differences between the two parties. As a result, more Americans know where to place themselves on a left to right scale when asked.

One long-running method for evaluating how ideologically sophisticated voters are is to look at how Americans discuss the parties and candidates when asked about what they like and dislike about each side. Historically this has shown few Americans use ideology or policy positions in describing their views. But political scientist Martin Wattenberg recently found that the percentage of voters who explain their choices with ideological concepts and labels — such as “liberal” and “conservative” — is on the rise, up from 25 percent in 1972 to 35 percent in 2012. He found an even larger jump in the number of voters who mentioned a few specific policy issues, such as being pro-choice or favoring tax increases as a way to justify whom they support, up from 3 percent in 1972 to 13 percent in 2012. Combined, nearly half of American voters now give reasons for their voting choices based on ideology or policy.

Wattenberg told me that voters used to voice generically positive views of their party, rather than talk about its positions or ideology. You might hear “the president brought us jobs” or “he’s a Democrat and so am I,” but you’d rarely ever hear the terms liberal or conservative or a list of the parties’ platform positions as a way to describe their views of their party.

As for what’s driving more Americans to think more like ideologues, Wattenberg points partially to increased education levels. The most educated voters have long been the most likely to think about politics in ideological terms and hold consistent policy opinions, and now there are more of them — in 1980, only 17 percent of Americans over the age of 24 had completed four years of college or more; by 2018, it was 35 percent.

But not all scholars are convinced that Americans are becoming more ideologically sophisticated. Political scientists Donald Kinder and Nathan Kalmoe found that most people still have opinions that do not track as consistently conservative or liberal and many still call themselves moderates or independents. For example, while most Democrats agree with mainly liberal policy positions, many Democrats overall still identify as moderates (even a few as conservatives). Meanwhile, Republicans might agree on ideological labels more than Democrats, but that doesn’t mean they hold more consistent policy positions.

In fact, one other possible explanation for what we’re seeing in the rise of ideology-driven politics is not that Americans are actually becoming more ideological; instead, they’re just more likely to repeat what political candidates and officials say. For example, Republican voters might now use the word “socialist” more often as an insult, but that does not mean they associate the term with its historical connotation or contemporary policy positions.

Ideology could matter in 2020, but we could be thinking about it wrong, too

On the one hand, voters’ increased ideological sophistication could enable the emergence of a more left-wing Democratic nominee in 2020, like Sanders. There is some evidence that his ideological language affected his voters in 2016, too. In Wattenberg’s data, Sanders’s supporters used language like “progressive” and “socialist” to describe their political views a lot more than other Democrats.

On the other hand, this kind of appeal may resonate with only a minority of the Democratic Party. After all, Sanders and Clinton voters did not differ much on their policy views, even though they were divided on whether they conceptualized politics in ideological terms. But with many voters caring more about picking a candidate who can defeat Trump than a candidate who agrees with them on the issues, it’s hard to know whether a candidate’s ideological appeal will help them wield a competitive edge in 2020.

Then again, there’s no reason Sanders can’t win the primary with a mix of ideological and not-so-ideological voters. Because even though Sanders does very well among very liberal voters, that doesn’t mean that his appeal is limited to them. Many voters see Sanders as electable, and he polls pretty well in head-to-head polls against Trump. And others might like Sanders’s consistency and authenticity, even if they don’t always agree with him. Take Sanders’s message of fighting against corruption and socioeconomic inequality. It is a pretty popular idea, and one that Democratic nominees have run on previously.

However, this doesn’t apply just to Sanders. The more moderate candidates will also need to widen their appeal beyond ideology. The race has now shifted to states with more diverse electorates, and many of the Democrats who do not think about their candidate preferences in ideological terms are nonwhite. Just as Sanders needs to recruit more than his ideological revolutionaries to build a majority, the more moderate candidates cannot succeed by merely saying Sanders is too far to the left. They, too, will need to make non-ideological appeals.

Of course, once the general-election race begins, running an ideological campaign could be a risk because it could leave out less ideological swing voters, but Democrats, including Sanders, have an effective alternative. Traditionally, Democrats have run campaigns that emphasize the groups that their party intends to help, including women, minorities, the poor, and especially the middle class. Whoever the nominee, “Who’s on your side?” may remain Democrats’ most popular message, appealing to both ideological and not-so-ideological voters.