A model of the White House is displayed at the D.C. Armory in Washington. (Andrew Harnik/AP)

Just over a week ago, the Democratic National Committee (DNC) voted to radically change the influence “superdelegates” have on their party’s presidential selection process. The superdelegates are unique to the Democratic Party and have long been controversial — but they became especially so in the 2016 primary fight between Sen. Bernie Sanders and Hillary Clinton.

Why did the DNC decide to change the system? And how will this affect the 2020 Democratic presidential primaries?

Presidential selection and the ‘superdelegate’ system

Since the mid-19th century, both parties have selected their presidential candidates at national conventions. At these conventions, delegates from each state vote to select the party’s presidential and vice presidential candidates. Originally, these state delegates were appointed by local party leaders. But starting in 1912, a number of states began to organize primaries or caucuses that allowed voters to select which candidate their delegates would support.

The number of primary states dramatically expanded after contentious conventions in 1968. Since the 1970s, all states have relied on primaries or caucuses to divide up their delegates. But Democratic Party leaders very quickly grew concerned about which candidates their primary voters were selecting. In 1972, George McGovern won the Democratic nomination — and in the general election, lost in a landslide to Richard Nixon. In 1976, Jimmy Carter — a political outsider — won the Democratic nomination and the general election, but alienated many congressional Democrats and much of the public while in the White House. In 1980, he lost in a landslide to Ronald Reagan.

After Carter’s 1980 loss, frustrated Democratic leaders wanted to regain influence in picking the nominee. A DNC committee proposed adding  “superdelegates,” spots given to party leaders who were free to vote for whatever candidate they thought would be most competitive. Since 1984, between 14 and 20 percent of the total delegates at Democratic conventions have been superdelegates. In 2016, these superdelegates were predominantly DNC members and elected officials.

What has the DNC changed?

The superdelegate system became particularly controversial during the 2016 presidential primary fight between Clinton and Sanders (I-Vt.). During those primaries, Sanders supporters attacked the DNC — ostensibly a neutral arbiter for all factions of the party — for purportedly supporting Clinton. Sanders supporters also criticized the primaries’ structure — including the superdelegates — as unfair to Sanders.

In response, the DNC has adjusted how it selects its presidential nominee. Earlier this summer, a DNC subcommittee voted to make it impossible for superdelegates to have the deciding vote on the first ballot at a national convention. In practical terms this means that superdelegates cannot vote in the first voting round if their support is going to decide the selection. If no candidate wins a majority in the first round, superdelegates get to vote in subsequent rounds. Thanks to DNC Chair Tom Perez — who lobbied heavily for the change — the DNC has now voted to implement the proposal.

How will this affect the 2020 Democratic primaries?

This change probably won’t make a big difference in how Democrats select their presidential nominee in 2020. But it might affect candidates’ strategy along the way.

In the old system, a candidate could theoretically win the majority of pledged delegates elected by primary voters — yet still lose the nomination. That could have happened if the race was really close and superdelegates supported the bare-minority candidate. That can’t happen under the new rules. A candidate who wins a majority of elected, pledged delegates will be the Democratic Party’s nominee.

But in reality, that theoretical scenario — in which superdelegates selected the minority candidate — never happened.

Between 1984 and 2016, in every case the candidate who won the most pledged delegates through primaries and caucuses was also supported by a majority of superdelegates. For example, in 2008 and 2016 the delegate race was incredibly close. In 2008, Barack Obama won just 51 percent of pledged delegates to Hillary Clinton’s 49 percent. In 2016, Clinton won a little over 54 percent of pledged delegates. In each case, Obama and Clinton were also supported by a majority of superdelegates: in 2008, approximately 66 percent of superdelegates supported Obama, while in 2016, 85 percent of superdelegates supported Clinton. Crucially, this means that both Obama and Clinton would have won their respective nominations if there had been no superdelegates.

But while superdelegates’ votes haven’t directly changed who won the nomination, they may matter in indirect ways. Superdelegates often announce who they’re supporting well before the convention. Candidates have in the past spent a lot of time and resources on trying to win their support.

So the new system may change the 2020 primaries after all. Candidates will now be relieved of having to woo superdelegates. They are still likely to care about getting party leaders’ endorsements. But they do not have to ensure that they get and keep superdelegates’ votes.

Voters, meanwhile, may think differently about which candidates could actually win the nomination. In 2016 Clinton already had several hundred superdelegates backing her before the first primary voter cast a ballot. Opponents of the old system argued that could affect voter behavior: Since the media reports on candidates’ delegate totals, including those of superdelegates, voters could have overestimated a candidate’s popularity. Political scientist Larry Bartels’s classic study of presidential primary voting behavior suggests that voters do consider a candidate’s likelihood of winning the nomination — which means that superdelegate support could theoretically affect primary voting.

All that means we’re not looking at a radical change in the race for the next Democratic presidential nomination. But Democrats can be assured that the process will be slightly more democratic, in the sense that ordinary voters — and not party elites — will have the final say. What’s more, party leaders may have a little less influence, with less ability to anoint a candidate before the first primary. Meanwhile, the DNC hopes that this relatively minor change will help restore the confidence of voters who thought the 2016 primaries were unfair.

Boris Heersink (@Boris_Heersink) is an assistant professor of political science at Fordham University.