Who is in charge of the presidential debates? Who gets to decide the time, location and rules? Why do candidates debate? These are all questions the Commission on Presidential Debates attempts to rectify as Americans prepare to head to the polls in November and choose between two major party candidates — Republican Donald Trump and Democrat Hillary Clinton — or, in some states, third party alternatives like Libertarian Gary Johnson and Green Party Jill Stein.

The CPD is a nonprofit, non-partisan corporation established in 1987 to “ensure that debates, as a permanent part of every general election, provide the best possible information to viewers and listeners,” its mission statement reads. It has sponsored every presidential debate since 1988.

While the CPD has an independent board of directors, it also has a staff that works on educational materials and provides research.

Funded by outside and private donors, the CPD doesn’t receive government money.

Here’s what you need to know about the organization:

1. It Was Founded in 1987 After a Study Encouraging the Major Parties to Pursue Debates

Before the establishment of the CPD in 1987 and its initial presidential debates the following year, debates between the two major party candidates weren’t guaranteed, nor were they organized.

“The 1984 experience, in particular, reinforced a mounting concern that, in any given election, voters could be deprived of the opportunity to observe a debate among the leading candidates for President,” the CPD states.

After that, the Georgetown University Center for Strategic and International Studies and the Harvard University Institute of Politics conducted separate studies and looked into how debates affect elections. The studies found candidates had a habit of declining debates or dropping them at the last second, according to the CPD.

The studies recommended the parties get together and figure out a way to get presidential debates in front of Americans. The CPD was born.

2. The CPD’s Governing Board Is Made Up of News Executives, Academics & Advisors

Frank Fahrenkopf Jr., and Mike McCurry are co-chairs of the CPD. Fahrenkopf, a Republican, is the former Republican National Committee chairman and helped President Richard Nixon’s re-election efforts in northern Nevada. McCurry, a Democrat, is the former press secretary for President Bill Clinton.

The commission is guided by a board of directors, which includes former Sen. John Danforth, Purdue University President Mitchell E. Daniels Jr., President and CEO of California Community Foundation Antonia Hernandez, former PBS news anchor and debate moderator Jim Lehrer, and more.

3. The 15 Percent Threshold Is Reserved for Mathematically Possible Candidates

Supporters of the Libertarian Party’s Johnson and the Green’s Stein are hoping their candidates can reach a 15 percent polling mark in five specific national polls. Once they hit that line, they’ll be allowed to debate, according to the rules established by the CPD.

On Sept. 16, the CPD announced only Trump and Clinton had qualified for the debates. The two third party candidates fell well below the 15 percent requisite, with Johnson at 8.4 percent and Stein at 3.2 percent.

Politico recently reported that Johnson is making enough of a splash that debate venues should draw up blueprints with a third lectern. Johnson’s numbers are around 8.8 percent in national polls, according to RealClearPolitics’ average, Politico reported.

“If someone came in and let’s say he was [polling] at 14.5 percent and the margin of error in five polls was 3 points, we are going to have to sit down and look at it,” Fahrenkopf told Politico. “But right now that person would not be included.”

First adopted in 2000, 15 percent “was preceded by careful study and reflects a number of considerations,” according to the CPD.

“Fifteen percent was the figure used in the League of Women Voters’ 1980 selection criteria, which resulted in the inclusion of independent candidate John Anderson in one of the League’s debates,” the CPD states.

The CPD states it sends out debate invitations after Labor Day. The debates are scheduled for Monday, Sept. 26, Sunday, Oct. 9 and Wednesday, Oct. 19. The vice presidential debate is Tuesday, Oct. 4.

4. The CPD Chooses the Moderators & Will Announce Them Soon

A single individual is always tapped to moderate the debates.

Although Trump has tried to negotiate debate terms before — like the 2015 CNBC Republican debate — the candidate has said he’s unsure of what he’ll do, depending on “certain moderators.”

“The bottom line is that the Commission does whatever the hell it wants,” Republican consultant Stuart Stevens told the Huffington Post.

The 2016 moderators include Lester Holt, Elaine Quijano, Martha Raddatz and Anderson Cooper, and Chris Wallace.

5. They Want to Educate You on How to Host a Debate

The CPD has resources for anyone hoping to host a debate — whether it’s issues forums, student debates or political candidates.

There’s a guide to understanding debates, how to establish and enforce rules, how to use a budget and include the media.

“This guide was prepared to answer the questions most commonly asked by the educational, civic and media organizations that host debates,” it states.