Why 15 Is the Magic Number for Third-Party Presidential Candidates Gary Johnson and Jill Stein

— -- For third-party presidential candidates Gary Johnson and Jill Stein, who are looking to break through in an election where the major-party nominees suffer from low favorability numbers, the opportunity to make their case directly to voters in nationally televised debates can be a game changer.

But before they can make it to the debate stage, they have to make it to a 15 percent average in selected national polls, and it’s not looking too good right now.

The Commission on Presidential Debates, which hosts the televised events, Monday announced the five polls it will use to decide who makes the cut: ABC News/The Washington Post; NBC News/The Wall Street Journal; CBS News/The New York Times; Fox News; and CNN-Opinion Research Corp.

So far, neither Libertarian candidate Johnson nor the Green Party’s Stein has hit the threshold in any one poll chosen by the commission, let alone on average.

Making It to the Magic Number

With less than six weeks to the first debate on Sept. 26, Johnson has come much closer to the 15-percent threshold than Stein. In one recent CNN/ORC poll, he hit his high mark of 13 percent support. Stein’s best performance so far is 6 percent.

Johnson, a former New Mexico governor, is polling at 10 percent on average in the five selected polls and Stein is polling at 5 percent, according to ABC News calculations.

There is another complicating factor for Stein in particular. While most major national polling organizations include the two third-party candidates in their questions, two of the five polls selected by the commission -- Fox News and CBS/NYT – do not include Stein’s name as an option for participants.

It is unclear whether the commission will use a zero when calculating her average percentage or make a final determination based only on polls that include her name. The commission did to respond to ABC News’ requests for comment.

In a new ABC News/Washington Post poll released last week, Johnson’s support didn’t break into the double digits, hovering at 8 percent, while Stein, a physician and activist, only half that level of support at 4 percent.

Why 15 percent?

The 15 percent threshold was a balance between "being sufficiently inclusive to invite those candidates considered to be among the leading candidates, without being so inclusive that invitations would be extended to candidates with only very modest levels of public support, thereby jeopardizing the voter education purposes of the debates,” according to the commission's website.

In its statement, the commission cited the “frequency” of polls, “soundness” of results and overall “reputation” as some of the factors it used to select the five polls.

Being on the Ballot

Another hurdle facing the third-party candidates is making it on the ballot.

In addition to the 15 percent requirement, the commission also requires that the candidates “appear on a sufficient number of state ballots to have a mathematical chance of winning a majority vote in the Electoral College."

Johnson, 63, is on pace to do so.

"We are on track to be on the ballot in all 50 states and the District of Columbia,” campaign communications director Joe Hunter said last week. “As of today, we are on the ballot in 39 states, and ahead of where we were in 2012 at this time.”

Stein, 66, is farther behind. She is on the ballot in only 26 states, including Washington, D.C., according to her campaign website.

But her campaign has filed petitions and signatures in about a half dozen other states, with more deadlines and additional states to come.