Why are there so many candidates for president?

Seven Democratic presidential candidates gathered on national television early in the 1988 campaign to debate each other.

The field of candidates, derided by Republicans as the “Seven Dwarfs,” pales in comparison to the 24 Democratic candidates who have – at last count – declared their candidacy for president.

The seven Democrats on the stage in 1988 represented an unprecedented number of candidates vying in a presidential primary. Now, 17 of the 24 declared Democratic presidential candidates have currently met the standards set by the Democratic National Committee to qualify for participation in this election cycle’s debates.

And in 2016 the GOP used two debate stages to accommodate the 17 declared candidates.

I study political parties and their role in electoral politics. And I believe the rise in the number of presidential candidates in recent years results from divisions within the party coalitions and from easier access to vital campaign resources – money and media – that were not present in previous election cycles.

Nine of the 17 Republican presidential candidates on stage with debate moderator Wolf Blitzer during the fifth Republican presidential debate on CNN, Dec. 15, 2015, in Las Vegas. AP/John Locher

The old way

Political parties are not monolithic organizations. Parties consist of a network of groups with different policy interests who work together.

For example, within the Democratic Party there are labor organizations, environmentalists and civil rights groups, each with different priorities. Each group would ideally prefer a candidate who will champion their ideas and strongly support their policy preferences.

But a primary filled with many candidates who attack one another risks harming the eventual nominee’s standing with voters.

Likewise, these divisive primaries may cause supporters of a candidate who fails to win the nomination to withhold their support of the nominee.

So to avoid the problems created by a divisive primary, these groups must coordinate behind a single candidate who may not be everyone’s – or anyone’s – first choice.

This requires the groups within the party to compromise, subordinating their group’s interests in favor of a win for the party.

In previous election cycles, where the average number of candidates who declared their candidacy and campaigned actively through the first primaries and caucuses was much smaller, these groups have worked together effectively to stand behind one candidate.

Money, media and staff

As my research shows, unified parties are able to discourage candidates from running or encourage them to drop out.

They do this by making it difficult for the candidates they don’t prefer to acquire the vital electoral resources that are necessary to win the nomination: media coverage, campaign funds and quality campaign staff.

Donors, staff and the media take cues from party elites about which candidates are the party’s choice. They are less likely to support, work for or cover those lacking the party’s support.

Reforms to the presidential nomination process in the early 1970s took choosing a nominee out of smoke-filled back rooms. But parties have continued to influence the outcome through their control of the money and other campaign resources necessary to win the nomination.