It’ll be a critical next few weeks for the presidential candidate most people haven’t heard of, Libertarian Gary Johnson.

The former Republican and former governor of New Mexico is hoping to gain a spot on the podium at the first presidential debate, scheduled for Sept. 26 at Hofstra University. To qualify, he must be averaging 15 percent in national polls. No minor-party candidate has done that since Ross Perot in 1992.

Johnson’s presence on stage with Democrat Hillary Clinton and Republican Donald Trump would change the dynamics of the race, Libertarians contend.

“It would truly be a game changer because the challenge for a third-party candidate is to become known,” said Joe Hunter, communications director for the Johnson campaign.

Johnson is nowhere near the 15 percent threshold yet. But he’s crept into double digits in some key states including Ohio and is hoping to continue to gain because so many voters dislike Clinton and Trump.

Together with his running mate, former Massachusetts Gov. William Weld, Johnson is trying to appeal to Republicans who have publicly disavowed Trump and people who supported Vermont Sen. Bernie Sanders in the Democratic primaries. Johnson also is hoping a series of town hall-style meetings on cable news channels this month will raise his profile.

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Hunter said the Johnson-Weld ticket — which will be on the ballot in all 50 states — has received “more attention than we’d otherwise expect” because of the quality of its candidates. But it “pales in comparison to the attention we would get by being on stage,” Hunter said.

“He still has a ways to go on that,” Marist College pollster Lee Miringoff said of Johnson’s chances for qualifying for debates. Marist’s recent survey found Johnson garnering 12 percent of the vote in Ohio and in Iowa, two key states for the election. His best showing appears to be Utah, where he’s at 16 percent.

Addressing his slow rise, Johnson told Newsweek: “A lot of that has to do with just how polarizing Clinton and Trump” are.

Johnson, who describes himself as “fiscally conservative, socially liberal,” says he’s for smaller government and, while he supports immigration reform, he opposes Trump’s idea of building a wall along the Mexican border. He picked up his first endorsement from a sitting congressman when Rep. Scott Rigell (R-Va.) said last week he couldn’t “in good conscience” support Trump.

Third-party candidates have made little impact over the last century in American presidential elections.

The most successful such candidates over the past four decades peaked in the summer before Election Day, only to fade by November — often because voters don’t want to “waste” a vote on a candidate who is unlikely to win, said Pace University political scientist David Caputo.

John Anderson, a former Illinois congressman, was polling near 20 percent at one point in the 1980 election before finishing with 7 percent of the vote.

Businessman Ross Perot led the 1992 race at one point. He eventually finished third, with 19 percent. However, it was a significant share, and many thought Perot hurt then-President George H.W. Bush and helped elect Democrat Bill Clinton.

In 2000, Green Party candidate Ralph Nader got just 3 percent of the vote. But Democrats saw the 97,000 votes Nader drew in Florida as crucial to throwing the critical state to George W. Bush, who beat Democrat Al Gore there by about 500 votes.

Unlike Anderson and Perot, Johnson hopes to peak late in the race.

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Caputo said the Libertarian has a “50-50 chance” of making the debate and might do well to target Sanders supporters.

“Obviously, Bernie and I part ways on economics. I don’t believe anything is free,” Johnson told Newsweek. But he said he agrees with the Vermont senator’s opposition to “crony capitalism” and military interventions overseas, and Sanders’ support of same-sex marriage, abortion rights and marijuana legalization.

Johnson said voting a third-party candidate isn’t “throwing away” a vote, but “voting for someone you don’t believe in” is.