Tonight as many as 100 million Americans, God help us, will be tuning in to watch the first debate between the two most hated presidential nominees since pollsters have been measuring candidates' unfavorability. Because the Commission on Presidential Debates, a technically nonpartisan nonprofit that was co-founded in 1987 by the Democratic and Republican parties to manage the terms of televised general-election discourse between White House aspirants, decided last October (with details ratified this August) to maintain as a participation threshold the unreasonably high average of 15 percent in national polls—a level no third-party candidate has attained in September of an election year since 1968—that means Libertarian Party nominee Gary Johnson, the highest-polling presidential outsider since Ross Perot in 1992, will be live-Tweeting instead of live-debating.

Which is a shame, and not just for those 8.5 percent of us who intend to vote for the guy. Having a debate with no Gary Johnson means that a whole host of pressing issues will not be treated seriously Monday night, and increasingly in the election itself. From fiscal sanity to free trade, foreign occupation to repealing prohibition, the Democratic and Republican candidates have abandoned sober policy-making in favor of centrally planned, government-aggrandizing promises that often flout their own parties' bases and traditions. In many important ways, there will be no adult on stage.

The following is an incomplete list of at least seven issue areas in which sensible and frequently popular viewpoints will not be offered by either of the "major"-party presidential candidates tonight, because a contrary Libertarian who will be on the ballot in all 50 states will nonetheless sit excluded, 28 miles away.

1) The country's grim long-term fiscal outlook. "Nobody's talking about balancing the federal budget," Johnson said on ABC's This Week with George Stephanopoulos Sunday. "Nobody's talking about the threat of a runaway government, nobody's talking about reforming Medicaid or Medicare."

This reticence to grapple with the America's perilous balance sheet is new, and actively dangerous. As I detail in Reason's October cover story, every State of the Union Address between 1997 and 2013 mentioned the need for long-term entitlement reform; but no more. And that's not because the situation has gotten any less dire. To the contrary.

In July, the Congressional Budget Office (CBO) pointed out that publicly held debt is "growing larger in relation to the economy than ever recorded in U.S. history," and that debt service alone will eclipse military spending in the next president's first term. "Large and growing federal debt over the coming decades would hurt the economy and constrain future budget policy," the CBO warned. "The amount of debt that is projected…would reduce national saving and income in the long term; increase the government's interest costs, putting more pressure on the rest of the budget; limit lawmakers' ability to respond to unforeseen events; and increase the likelihood of a fiscal crisis."

Yet Hillary Clinton wants to expand Social Security and reduce the age for Medicare opt-in eligibility to 55, in addition to passing "the biggest investment in new, good-paying jobs since World War II," making "college tuition free for the middle class and debt-free for all," liberating "millions of people who already have student debt," and helping "more people learn a skill or practice a trade and make a good living doing it." How the heck would she pay for expanding an already bloated and unaffordable government? "Here's how," she said in her Democratic National Convention speech. "Wall Street, corporations, and the super-rich are going to start paying their fair share of taxes."

Donald Trump, to his credit, does talk about the "disastrous" national debt. To his discredit, however, Trump's economic plans are estimated to increase that debt much faster than Clinton's, which is what happens when a Republican candidate wins a primary on protecting entitlements, drastically increasing military spending, and out-spending the Democrat on infrastructure.

There is a broad middle of American public opinion that is legitimately anxious over a national debt that was doubled under George W. Bush from $5 trillion to $10 trillion* (an increase that then-candidate Barack Obama characterized as "un-American"), and then doubled again over the next eight years. That middle will not be represented on stage tonight.

2) Federalism. Of the many ways that Donald Trump flouts the letter and spirit of the United States Constitution, one of the least examined is his ongoing disregard for the 10th Amendment, which states that "The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people." His statement last week that "I would do stop-and-frisk—I think you have to," indicated a man with zero instinct for recognizing the proper limitations on federal power.

The woman he's running against literally wrote the book on inviting the federal government to alleviate intimate concerns. It Takes a Village remains both a startling ur-text of modern technocratic progressivism and useful primer on Clinton's hierarchy of government values (basically, if you can argue it's "for the children," she's in).

As the former governor of New Mexico, Gary Johnson sees federalism not just as a way of generating creative solutions to difficult problems like medical-entitlement reform, but—and this is crucial—as a decentralizing value to be embraced even if it does not lead immediately to his preferred policy goals. So it is that the man most famous for being the first major U.S. politician to support ending the drug war has repeated ad infinitum that beyond repealing the asinine federal prohibitions and marijuana-classifications, a Johnson administration would let state and local governments figure the rest of that stuff out.

Federalism was the magic-bullet solution in a mini-run of political books during President Barack Obama's second term, from Charles C.W. Cooke's The Conservatarian Manifesto to Nelson Hultberg's The Golden Mean. It was even a semi-popular idea on the left during George W. Bush's second term. Yet the only presidential candidate talking about it is Gary Johnson.

3) Trade. Forget for a moment the controversies (libertarian or otherwise) over the Trans-Pacific Partnership, and instead drill down into one salient and gruesome fact: Both candidates on the debate stage tonight are campaigning on promises to punish U.S. companies for relocating.

Hillary Clinton would charge companies moving overseas an "exit tax." Trump is even more ominous, if less specific: "If companies want to leave Arizona and if they want to leave other states," he said during his big immigration speech in Phoenix last month, "there's going to be a lot of trouble for them. It's not going to be so easy. There will be consequence. Remember that. There will be consequence. They're not going to be leaving, go to another country, make the product, sell it into the United States, and all we end up with is no taxes and total unemployment. It's not going to happen. There will be consequences."

Gary Johnson does not believe that the federal government should punish U.S.-based companies for changing addresses.

4) Military interventionism. In every campaign appearance, Gary Johnson emphasizes that U.S.-led "regime change" and foreign occupation are almost always bad ideas that lead to "unintended consequences." Agree or disagree with this argument, it's one that resonates with broad swaths of American public opinion on both sides of the political aisle. And it won't otherwise be represented tonight.

Hillary Clinton continues to defend the disastrous, U.S. led regime change in Libya that she helped lead as "smart power at its best," and has spent the 21st century as a largely unrepentant warmonger. Donald Trump, while introducing some long-overdue war-criticism to Republican politics, also blames the rise of ISIS on U.S. withdrawal from Iraq, promises to "bomb the shit out of them," and advocates the type of long-term occupation required to control that country's oil fields.

5) Domestic surveillance. Hillary Clinton still defends the PATRIOT Act, wants to ban encryption and give the feds access to your iPhone, and denies that Edward Snowden is even a whistleblower. Donald Trump supports re-authorizing the PATRIOT Act, supports the National Security Agency's bulk metadata collection, and has repeatedly called for Snowden's execution.

Gary Johnson would repeal the PATRIOT Act, dismantle the NSA, and pardon Edward Snowden.

6) Free speech. "Trump vs. Clinton Is Terrible News for Fans of Free Speech and the First Amendment," ran the headline of a piece by our resident constitutionalist Damon W. Root this May. "Both candidates have abysmal records on First Amendment issues."

To cite one of many possible examples, both candidates, within 24 hours of each other last December, responded to the San Bernardino terrorist attack by proposing to shut down parts of the Internet, and then mocking those who would object on free-speech grounds. (One of them said "You're going to hear all of the usual complaints—you know, 'freedom of speech,' etc.," and the other said, "Somebody will say, 'Oh, freedom of speech, freedom of speech.' These are foolish people.")

Trump wants to "open up the libel laws" (as if a president could; see #2). Clinton has advocated for a half-dozen laws whose basics were eventually declared unconstitutional by the Supreme Court on First Amendment grounds.

"I am gung-ho for free speech, the Constitution, the First Amendment!" Gary Johnson said on Fox Business Network's Varney & Co. last month. While that commitment has been called into question over Johnson's not-especially-coherent comments on freedom of association and campaign-finance restrictions (he's against the latter, but in return for mandatory disclosure of funding sources), his default position on issues from "Net Neutrality" to campus speech codes remains favoring individual choice over government control.

7) Prohibition. Donald Trump thinks we can solve the "heroin epidemic" by building a border wall with Mexico. Hillary Clinton thinks we should throw $10 billion at it. Gary Johnson, whenever he is asked about the increase in opoid-related overdoses, points out that black markets make drugs more dangerous (while also emphasizing that this is ultimately a state issue; see #2).

Hillary Clinton in 2009 uttered of one of the single dumbest scare-quotes ever about legalizing marijuana ("There is just too much money in it"), though at least she, like her opponent, would continue the federal government's semi-tolerance of legal marijuana in states like Colorado. Gary Johnson's views on the issue are obviously well known, scary as they might be to the Marc Thiessens and Rolling Stone magazines of the world.

It's plausible that the 2016 presidential campaign will soon have a BD/AD moment—as in "Before Debate" and "After Debate." Such are the stakes, the level of interest, and the unpredictability of Donald Trump. But as the nation careens toward fiscal calamity, it's worth noting that some of the most critical questions were edited out long before the debate began. By excluding the Libertarian Party nominee, the Commission on Presidential Debates has made a mockery out of its stated commitment to "voter education," and thus contributed to the postponement of America's day of reckoning. It's up to the rest of us to insist on discussing what the old-party candidates will not.

* (was "million," due to authorial stupidity)