Toward the end of the first Democratic presidential debate, CNN’s Anderson Cooper turned to former US senator and Rhode Island Governor Lincoln Chafee and asked, “Edward Snowden, is he a traitor or a hero?”

“I would bring him home,” Chafee said of the American whistle-blower who leaked classified National Security Agency documents that exposed details of the NSA’s surveillance programs in the United States and abroad.

“Bring him home, no jail time?” asked Cooper.

“[What] Snowden did showed that the American government was acting illegally for the Fourth Amendment,” said Chafee. “So I would bring him home.”

Cooper then turned to former secretary of State Hillary Clinton, who was of a different opinion altogether.

“He broke the laws of the United States,” said Clinton, who claimed Snowden wasn’t really a whistle-blower but someone who “stole very important information.”

“I don’t think he should be brought home without facing the music,” she concluded.

Vermont Senator Bernie Sanders was more nuanced in his response.

“I think Snowden played a very important role in educating the American people to the degree in which our civil liberties and our constitutional rights are being undermined,” said Sanders. But the Vermonter added that “he did break the law, and I think there should be a penalty to that. But I think what he did in educating us should be taken into consideration…”

No matter where people stand on the question of pardoning Snowden, the exchange Cooper invited was a healthy one for a society that must wrestle with questions about balancing security and liberty. Candidates expressed distinct opinions. They disagreed. And citizens were invited to consider the issues that arise when official secrecy and government lawlessness are challenged.

My only objection was that the CNN host did not follow up—especially on the Fourth Amendment issues raised by Chafee and the claim that Snowden should be seen as a criminal rather than a whistle-blower.

But at least the exchange was had. And—thanks to Chafee—dissents from mainstream media and political assumptions were aired.

That’s what is supposed to happen in debates. They’re supposed to be about ideas—especially ideas that push the discourse beyond repetition of conventional wisdom.

Unfortunately, the Commission on President Debates, which was set up more than a quarter-century ago to police presidential politics on behalf of the Democratic and Republican parties, has no taste for the robust and vibrant exchange of ideas that is vital to democracy.

So, this year, while Democrat Clinton and Republican Donald Trump have been invited to the debate stage, Libertarian Gary Johnson and Green Dr. Jill Stein have been told to stay away.

Never mind that Johnson frequently polls in double digits and that Stein is posting some of best numbers in the history of her party. Never mind that Johnson, a former governor of New Mexico, is on all 50 state ballots and that of the District of Columbia; or that Stein is on at least 44 state ballots and that of the District of Columbia. Never mind that both have met what should be the baseline standard for inclusion in fall debates: They have gotten on enough ballots to win the electoral votes that are necessary for election to the presidency.

Johnson and Stein have been told by the CPD that they cannot debate.

That’s wrong—wrong for democracy, and wrong for the national discourse.

Of course Johnson and Stein should participate in the debates with Clinton and Trump. All four of these contenders have garnered the support needed to get on enough state ballots to be elected president. Yet, by setting an absolutely arbitrary 15 percent threshold for getting into the debates, the CPD has denied Johnson and Stein a chance to participate. The CPD’s standard is absurd and antidemocratic. In Britain, France, Canada, and other functioning democracies, debates feature the candidates of multiple parties—including credible parties that are polling in single digits. In the Democratic and Republican primaries in the United States, debates featured the vast array of front-runners and insurgents—including candidates who have been polling less than Johnson or Stein as the fall campaign has geared up.

But this is not just about fairness, or respect for democracy. This is also about the character and quality of the debate.

Anyone who wants to hear a real exchange of ideas, anyone who wants more than predictable talking points (and, with Trump on the stage, predictable cheap shots), anyone who wants something akin to an actual debate, should be petitioning the CPD and supporting struggles in the courts of law and the courts of public opinion to open up the debates.

Just take the question of whether American Civil Liberties Union Executive Director Anthony Romero is right when he argues, “Cases like Edward Snowden’s are precisely the reason the president’s constitutional pardon power exists.”

The discussion about whether to welcome Snowden back to the United States has taken on new energy with the release of Oliver Stone’s film on the whistle-blower and with the launch of a campaign for a presidential pardon.

Clinton has stated her position, and Trump said in a March Republican debate: “When you just asked the question about Snowden, I will tell you right from the beginning, I said he was a spy and we should get him back. And if Russia respected our country, they would have sent him back immediately, but he was a spy. It didn’t take me a long time to figure that one out.”

Both should be pressed on their statements, and on their attitudes regarding Americans who blow the whistle on wrongdoing and unconstitutional acts by their government. And Johnson (“If I were president of the United States, I would certainly look into actually pardoning Edward Snowden”) and Stein (“I would publicly acknowledge his heroism”) should be there to offer alternative views.

The inclusion in the debates would probably help both Johnson and Stein. But that isn’t the point of advocating that the Libertarian and the Green take the stage. The point is that the inclusion of Johnson and Stein would help the debates—by broadening the range and quality of the discourse on hot-button issues, like pardoning Edward Snowden.