But the truth is that whatever happens tonight is of vital importance, for the election and for the future of American politics. Here’s why:

1. The election may be closer than we think.

Yes, Bloomberg has Clinton up by 9% nationally, but other polls give smaller numbers. In particular, Rasmussen and the Los Angeles Times both have Clinton and Trump tied, though it should be noted that both polls have favored Trump throughout the campaign. Still, a Reuters poll released today had Clinton up by only 4%. That’s a substantial lead for the modern era, but it’s not insurmountable.

2. State races are closer.

A recent CNN poll had Clinton up by just 1% in North Carolina. In Ohio, CNN shows Trump besting Clinton by 4%. Other swing states, like Pennsylvania and Florida, look more distant, but if Trump manages to connect with voters in those states tonight, movement is possible.

3. There is some precedent for a Trump-sized comeback, and it started with a debate.

Trump-supporters, and Trump himself, would do well to read up on the 1980 election, when Republican Ronald Reagan beat incumbent Democrat Jimmy Carter by nearly 10% of the national vote after trailing behind Carter by as much as 6% in mid-October, which is approximately where we are now in the cycle.

The turning point in that election is often seen as the presidential debate. There was only one that year because of a fight regarding whether third-party candidate Jack Anderson would be invited, and it finally occurred just a week before the election, on October 28th.

Carter was hard on Reagan during the debate, framing him as a hothead who couldn’t be trusted with nuclear codes. (Sound familiar?) He also attacked Reagan on a number of policy issues, including his supposed opposition to national healthcare. Reagan’s famous riposte to that criticism, “There you go again,” would go on to become a signature Reagan catchphrase, in large part because it worked against Carter’s narrative, showing a smiling Reagan laughing off criticism. Viewers wanted to trust him.

The debate also had a major Carter gaffe, when the president said he asked his 12-year-old daughter about policy goals. As the incumbent, Carter was trying to benefit from his status as commander-in-chief. The quote was particularly harmful for his campaign since it showed instead a Carter that was dangerously naive.

A close-reading of the 1980 debate then presents a quick strategy for Trump to use tonight: have one good quote that shows you’re calm and likable in the face of dissent, then wait for your opponent to drop one dumb line that will undercut her credentials. That’s all it took for Reagan to get his stunning 10% victory.

Of course, there are many reasons that the 1980 election is unlike the current one and reason to believe that there are simply fewer swing voters today, but it’s also important to remember that Trump doesn’t need to increase his polling by 16% like Reagan to become president. Half of that, according to most polls, would be enough.

4. Even if the debate isn’t won but Trump, it’ll be crazy, and it’ll affect U.S. politics in ways we can’t imagine.

Reagan won his 1980 victory through careful debate prep–there was actually a whole political scandal about him being too well-prepared–so it seems unlikely that Trump will take the Gipper’s example there. Yet even if Trump can’t use the debate to up his polling, he still has the power to change American politics tonight.

Before the last debate even began, Trump was holding a press conference with women accusing Bill Clinton of assault. There’s no precedent for attacks on a candidate’s spouse (nor, to be fair, is there precedent for a spouse like Bill Clinton). There’s also no precedent for the kind of psychological warfare that Trump employed by making sure each of those accusers was in the audience during the debate itself.

If Trump does lose the election, tonight’s debate might be most important in terms of whether Trump doubles down on recent claims that the election is “rigged,” which is a whole different but similarly unprecedented rhetoric. The last debate had a live viewership of 66.5 million, with many millions more seeing highlights afterward. If Trump successfully sews seeds of doubt in the American electoral process to an audience of that size, election turnout could be down for generations, if the process even remains in its current state.

Here’s what we know for sure: Chris Wallace is moderating the debate, and he’s known for hard-hitting questions. It’s when Trump is on the defensive that he tends to be the most volatile. Expect blood.