Now that the midterms are over, the speculation and leaks about who will run for president in 2020 begin in earnest — even though we’re still more than a year out from the Iowa caucus. This is all part of the much-talked-about “invisible primary,” where bids for office aren’t yet public and the primary season hasn’t truly kicked off. For now, many politicians will politely demur when asked whether they’ll run. But that doesn’t mean those conversations aren’t happening behind the scenes now. We have some idea of how this process has worked in the past, but 2016 brought some surprises and revealed underlying tensions between party elites and their voters. Which raises the question: Is everything different now?

How we thought the invisible primary worked

A 2008 book called “The Party Decides” explains how party elites maintain control over the presidential nomination process, and the book has been hugely influential in shaping our understanding of how the nominating process works. The book’s authors argue that elected officials, often responding to pressure from a party’s core constituencies (like evangelical Christians for Republicans or organized labor for Democrats) coordinate and signal agreement on presidential nominees through endorsements. FiveThirtyEight has even tracked endorsements in previous presidential primaries.

The book’s central idea is that party elites narrow down the playing field before the first caucuses and primaries ever take place. For example, the authors describe how then-Senate Majority Leader Bob Dole won the approval of the Christian Coalition in his 1996 bid for the Republican nomination and, as a result, the backing of influential Southern politicians. The endorsement of this wing of the party changed the competitiveness of the primary by taking a key group away from right-wing populist Pat Buchanan and giving it to Dole, which helped him clinch the nomination.

But the book also cautions that appealing to a party’s base isn’t always enough to win. Party leaders also want to pick a candidate who is electable — or has the political skill to appeal to voters outside the party’s core to win a national election. For instance, Dole’s credentials and party support resonated with staunch Republicans, but weren’t enough for him to beat popular incumbent Bill Clinton. Arguably, Democrats’ selection of then-Senator John Kerry to challenge George W. Bush in 2004 was all about candidate electability. The book suggests that party elites turned away from a second Al Gore run despite his strong polls, and similarly decided against backing the populist message of Howard Dean, who some leaders saw as an unlikely bet in the general election. But as we saw in the 2016 presidential election, the mechanics of selecting a candidate who appeals to both the party base and the party elders may be fracturing.

What happened in 2016

We would expect that when party elites choose whom to endorse, they pay close attention to which candidates appeal to voters. And generally speaking, the types of candidates who attract the most voters run highly visible campaigns while drawing support from influential elites in the form of either interest groups or prominent politicians.

But 2016 challenged this dynamic, especially in the Republican presidential primaries. Some elites coalesced, if a bit slowly, around Jeb Bush in 2015, but the polls never caught up. And all of that early cash — around $130 million — didn’t help him much. Marco Rubio pulled ahead in the party support race during the early primaries, but voters didn’t warm to him either. Instead, many preferred the partially self-funded celebrity Donald Trump.

Indeed, much of what we thought we knew about electability turned out to be wrong. Trump, a candidate with no electoral experience, won both his party’s nomination and the presidency. But it wasn’t just Trump’s unusual candidacy that challenged our understanding of the invisible primary. The energy that surrounded Bernie Sanders surprised Democratic leaders as well. A self-described Democratic socialist became a national political figure and ran a competitive race against the party’s anointed nominee, Hillary Clinton. Sanders didn’t have Clinton’s backing among party elites, but he still managed to draw big crowds at campaign rallies and fund his campaign with the help of small donations — two similarities his campaign shared with Trump’s.

In the end, Sanders didn’t win the nomination and Democratic elites got the nominee they wanted. But they found themselves going into the general election having fought an unexpectedly tough primary.

What will it mean for 2020?

The 2018 midterms showed that Democrats can still be competitive in the Midwest, the states largely responsible for Trump’s 2016 victory — but it also indicated that Democrats might be poised to make inroads in the Southwest. This could potentially fuel a fight about what kind of candidate to nominate in two years. Democratic leaders will want to whittle down what could be an awkwardly large group of candidates, but if the winnowing is too aggressive, it could create a backlash like the one we saw in 2016.

To be clear, the invisible primary will happen. We’ll just have to see what form it takes this year. Candidates will court elites, donors and voters — even if doing all of that at once proves tricky. We should still expect endorsements and money to pour in, even if it’s less clear than before what they mean. Sometimes the party has a favorite in mind, and sometimes the invisible primary can show that someone junior and relatively unknown, like Barack Obama in 2008, has the backing to be a true first-tier candidate. But in a field that’s likely to have many strong candidates, an invisible primary may not do much to differentiate among them. The party may need an actual primary for that.