On the eve of the first debate between Donald Trump and Hillary Clinton, I thought I would write down some of the precepts and maxims I have used to understand press behavior during this long and startling campaign season. If I have done this right, you should be able to test the usefulness of my list in the final six weeks of the U.S. election. (And during coverage of the debates!)

A word on how I came up with this list. I’ve been a close reader and critic of campaign coverage American-style since 1988. That’s eight “cycles,” as people in the industry say. After I started PressThink in 2003, I could write about the gatekeepers without their permission — hurray for blogging! — and so my pace increased during the 2004, 2008, and 2012 elections. This year I have done a little less at my blog (eight pieces since May 2015, plus one for the Washington Post) and put more into the real time conversation on Twitter, which includes most of the people doing campaign coverage, as well as the heaviest users of it.

Over that stretch I have tried to develop my own pressthink in reply to “theirs,” meaning the ideas most campaign journalists have about their work, and the explanations they tend to give when criticized for it. I tried to summarize the first 20 years of this tension in my 2011 lecture: Why Political Coverage is Broken. What I said there is still basic to how I do my criticism, but Donald Trump’s spectacular intervention has raised the stakes and altered the terms of the debate.

Trump is not a normal candidate and can’t be covered like one. Journalists have finally accepted that. Just the other day Dean Baquet, editor of the New York Times, said this about Trump

He’s been hugely challenging. I don’t think we’ve ever had somebody who in my time as a journalist so openly lies, and that was a word that we struggled to actually utter. We’re used to, I think as journalists, we’re used to philosophical debates, like one party thinks we should go to war on Iraq, makes its case—exaggerates its case, we now know. But there are warring philosophies. I’ve never quite seen anything like [Trump], and I think it’s a real challenge for us.

Elections were about warring philosophies. Journalists sat in the press box and brought you the action. Baquet admits: this organizing image no longer organizes much. But even his phrase “hugely challenging” understates it, I think. Here are the major propositions I have been using to understand this unique and perilous moment.

1. Political journalism rests on a picture of politics that journalists and politicos share.

As practiced by the “mainstream media” (the professionals who work at NBC, ABC, CBS, CNN, PBS, NPR, the AP, the New York Times, the Washington Post, the Wall Street Journal, the Los Angeles Times, USA Today, Reuters, Bloomberg, Politico, Time magazine) political journalism is constructed — it rests entirely — on a mental picture of the American system in which the two major parties are similar actors with, as Baquet put it, “warring philosophies.”

Elections are the big contests that distribute power between them. The day-to-day of politics is a series of minor battles for tactical advantage. The press is part of this picture because it distributes attention, but — in this view of things — it does not participate in politics itself. It reports on battles large and small, questions the power holders, tries to reveal machinations going on behind the scenes and generates public interest in the drama of politics. But it is unaligned with the major players and unaffected by the outcome of the contests it chronicles.

To report successfully on such a system you need sources who trust you inside both parties. You need people in both parties who will return your calls and have drinks with you at the Des Moines Marriott. The simplest way to guarantee that is to look at politics in the same way that people in the party establishments do. The political pros who staff the committees and run the campaigns and consult with the big players are the closest readers of political journalism and closest in outlook to the journalists who consider reporting on politics their profession.

I called this a mental picture, but it’s more than that. It’s a stable framework within which work can be done, coverage can be planned, knowledge can be refined, reputation can be won, careers can be built. The image of two similar parties with warring philosophies that compete for tactical advantage also positions the mainstream press in a comfortable way: between partisan players as chronicler, questioner and referee. Among those most comfortable with that position: media owners and managers hoping to alienate as few people as possible.

In other words: powerful forces keep the mental picture in place.

2. Asymmetry between the parties fries the circuits of the mainstream press.

Now imagine what happens when over time the base of one party, far more than the base of the other, begins to treat the press as a hostile actor, and its own establishment as part of the rot; when it not only opposes but denies the legitimacy — and loyalty to the state — of the other side’s leader; when it prefers conspiracy theory to party-friendly narratives that at least cope with verified fact; when it is scornful of the reality that in a divided system you never get everything you want.

This is the thesis that Thomas Mann and Norman Ornstein developed in their 2012 book, It’s Even Worse Than It Looks. They are think tank scholars with PhDs and Washington insiders who were frequently called on by journalists to explain trends and furnish quotes. They had incentives the same as journalists to stay on conversant terms with politicos in both parties. Mann and Ornstein came to the conclusion that something had changed in the Republican Party. Their summary of it:

The GOP has become an insurgent outlier in American politics. It is ideologically extreme; scornful of compromise; unmoved by conventional understanding of facts, evidence and science; and dismissive of the legitimacy of its political opposition. When one party moves this far from the mainstream, it makes it nearly impossible for the political system to deal constructively with the country’s challenges.

Four years later, Dan Balz of the Washington Post, probably the most respected figure in the political press, admitted that Mann and Ornstein were onto something. “They were ahead of others in describing the underlying causes of polarization as asymmetrical,” he wrote. Why did it take four years? (In 2012 and 2014 Balz was noncommittal about the thesis.) Two answers: asymmetry fries the circuits of the mainstream press… and Trump.

Because journalists rely so heavily on that mental picture I described, they stick with it as the anomalies build up. Mann and Ornstein had tried to warn Balz and his colleagues about this:

We understand the values of mainstream journalists, including the effort to report both sides of a story. But a balanced treatment of an unbalanced phenomenon distorts reality. If the political dynamics of Washington are unlikely to change anytime soon, at least we should change the way that reality is portrayed to the public.

This advice was ignored at the time. But now it cannot be. For Trump is that “insurgent outlier” described by Mann and Ornstein. In his nativism, xenophobia, “identity politics for white people,” and loose talk about nuclear weapons he is the ideologically extreme. Like the deformed party Mann and Ornstein wrote about, he is “scornful of compromise; unmoved by conventional understanding of facts, evidence and science,” and dismissive of the legitimacy of his opposition. He makes things up and doesn’t care if they are fact-checked and found to be lies. He whips up hatred of the press almost to the point of encouraging violence.

Hillary Clinton, for all her problems, including a tense and hostile relationship with the press, is a conventional politician running a conventional campaign that observes the norms of American politics.

That’s asymmetry. Asymmetry is in many ways the story of the 2016 campaign. But it fries the circuits of the mainstream press. Resistance to acknowledging this is strong because so much crumbles if symmetry crumbles. It’s not that it can’t be done. It can be:

All politicians bend the truth to fit their purposes, including Hillary Clinton. But Donald J. Trump has unleashed a blizzard of falsehoods, exaggerations and outright lies in the general election, peppering his speeches, interviews and Twitter posts with untruths so frequent that they can seem flighty or random — even compulsive.

But political journalism isn’t wired for this. It’s wired to safely reproduce the image of two comparable parties with different philosophies. As Ezra Klein noted, the fact that so many in the Republican establishment are appalled by their own nominee has made it easier for some journalists “to cover Trump as an alien, dangerous, and dishonest phenomenon.” But this is not a break with the mental picture I described. It’s a kind of permission from the insiders to go after the guy as threat to the system they share with journalists.

No one is more sold on symmetry than the people who produce political coverage at CNN, which sees itself as steering a middle course between Fox and MSNBC. This has led to a bizarre pattern in which CNN’s paid “contributors” like Corey Lewandowksi faithfully represent Trump by airing the same falsehoods the candidate has been using while freelancing some of their own. CNN hosts sometimes have to correct their own people on air and tell them to stop making stuff up— when it’s CNN who is paying them to play Trump in the first place! (See Bryan Curtis in The Ringer for examples.)

3. Campaign coverage had problems akin to the build up of “technical debt.”

This is an analogy I picked up from Josh Marshall of Talking Points Memo. (Technical debt is Ward Cunningham’s concept.) Marshall explains it this way:

If we do a project in a rough and ready way, which is often what we can manage under the time and budget constraints we face, we will build up a “debt” we’ll eventually have to pay back. Basically, if we do it fast, we’ll later have to go back and rework or even replace the code to make it robust enough for the long haul, interoperate with other code that runs our site or simply be truly functional as opposed just barely doing what we need it to. There’s no right or wrong answer; it’s simply a management challenge to know when to lean one way or the other. But if you build up too much of this debt the problem can start to grow not in a linear but an exponential fashion, until the system begins to cave in on itself with internal decay, breakdowns of interoperability and emergent failures which grow from both.

Josh thought this had happened with the Republican Party. For example, “a large portion of the GOP is not satisfied with what can realistically be achieved by conventional political means.” It should have found a way to put this to its most demanding supporters, but there was always a reason to avoid that massive reckoning. This left it vulnerable to a huckster and fantasist like Trump. Or: “Can Marco ‘Establishment’ Rubio really get traction attacking Trump for having no specific plan to replace Obamacare when Republicans have spent the last five years repeatedly voting to repeal Obamacare without ever specifying a plan to replace it with?” Again: they never got around to it. This left them vulnerable to Trump.

I read Marshall’s analysis and thought: the same thing happened in a different way to political journalists. They should have found a way to deal with “a balanced treatment of an unbalanced phenomenon distorts reality,” but they kept putting it off, even though they knew that something was happening to the Republican Party that wasn’t happening to the Democrats. They should have built asymmetric polarization into their mental model but it was a lot of work and “both sides do it” was too comforting, too attractive.

More debt: They should have done something about the uniformity of approach from cycle to cycle and newsroom to newsroom but it was too easy to keep doing it the way they had always done it. (Two exceptions: they added fact-checking; and influenced by Nate Silver, they got more sophisticated about polling.) They should have lessened their dependence on establishment voices and political professionals but the shared sensibility — which I have called the savvy outlook — was too hard to overcome. They should have admitted that they had become part of the political class, but it required them to retire too many illusions about themselves.

4. Trump’s campaign upends the assumptions required for traditional forms of election-year journalism even to make sense.

I made this argument in the Washington Post in July. Campaign coverage is a contraption that only works if the candidates behave in certain expected ways. Up to now, they always did. But Trump violates many of these expectations. For example:

Imagine a candidate who wants to increase public confusion about where he stands on things so that voters give up on trying to stay informed and instead vote with raw emotion. Under those conditions, does asking “Where do you stand, sir?” serve the goals of journalism, or does it enlist the interviewer in the candidate’s chaotic plan?

Here’s a more granular example. Up to now campaigns for major party nominees tried to make sure that what the campaign was saying (and the campaign manager, the running mate, the chair as titular head…) reflected what the candidate was saying. If the campaign put out a message contradicted by the candidate, that was a problem. Why? Because mixed messaging confuses the voters and makes the campaign look dumb. Therefore an interview with the campaign manager, the running mate, or some other surrogate was a window into the candidate’s thinking. It had journalistic value for that reason.

The Trump campaign breaks this practice. If Donald Trump calls NBC’s Lester Holt a Democrat (in fact he’s a registered Republican) and attacks him as part of an unfair system, Trump’s campaign manager, Kellyanne Conway, is later free to say that Holt is a “respected, brilliant newsman” who will do a great job as moderator of the first debate. An on-the-ball journalist can ask: hey, which is it? But that’s a practice with a premise. The premise is that a presidential campaign wants to put out a consistent message to avoid confusing people, and to deny journalists a “gotcha” moment. What if that premise is false? The rationale for interviewing the campaign manager, the running mate, or some other surrogate collapses. They say one thing, the candidate says something else and the confusion is not considered a problem. It may even be a plus.

Again and again with Trump, journalists find themselves in this position: persisting with familiar practices that don’t really make sense because the premise behind them has collapsed— collapsed for one candidate, but not the other. And remember: asymmetry fries the circuits of the mainstream press.

5. Hillary Clinton would like to avoid the press. Trump is trying to break it.

I will outsource the fact pattern to Erik Wemple, media columnist for the Washington Post, and the background on Clinton to Politico. But I would add that Trump’s threat to the press goes far deeper than his flagrant abuse of journalists and the threatening noises he has made about libel law.

When I say he’s trying to break the press, I mean the entire system that gives honest journalism a role in the republic. Trump is running against such basic notions as:

“we need a fact-based debate or there can’t be consent of the governed;”

“there’s a public record that cannot just be wiped away;”

“a candidate’s position on major issues should be made clear to the voters;”

“lying cannot become a universal principle in politics without major damage to our democracy.”

Not only is he running against such fundamentals, the continuity of which is assumed by all forms of campaign coverage, but journalists are the ones who understand best his assault on these basic principles. They’re living it every day. Of course, he’s running against them, too.

A political style that mocks the idea of a common world of facts — and gets traction with that view — is an attack on the very possibility of honest journalism. Campaign journalists have to find a way to oppose this style without becoming election-season opponents of Trump himself, which is not, I think, their proper role. Nothing in their training or tradition would have prepared them for this moment.

6. A candidate the likes of which we have not seen requires a type of coverage we have never seen.

I agree with the Atlantic’s James Fallows about Trump. “No one like him has gotten this close to the presidency in modern times.” Which is not to say he came out of nowhere, or that there is no precedent for his political style. A long series of developments left the presidential nominating system and the Republican party vulnerable to Trump. A long series of developments, which I tried to summarize here and here, also left political journalism unprepared for the challenge of covering this campaign.

But now we’re here and novelty demands novelty. If journalists are to rise to the occasion in the final six weeks of this campaign, they will have to find a style of coverage as irregular as Trump’s political style. There are powerful forces working against this. But if they don’t try, they are likely to regret it for the rest of their careers.