At this moment, polls show a strong upswing for Donald Trump’s campaign. He’s made real ground on Hillary Clinton, closing the gap between them by consolidating the Republican Party behind his candidacy. Clinton, meanwhile, is fighting a contentious primary, which keeps her from doing the same. There’s still a strong case to make that Donald Trump is a long shot for the White House—that he’s too unpopular with too many Americans outside the Republican Party and that if the Obama coalition holds, he loses.

At least, that’s what I think. But humility is a virtue, and life is volatile, even if elections often aren’t. That Trump is a poor bet for November doesn’t mean he couldn’t win. He could. Which raises an obvious question: How would it happen? And finding an answer here isn’t too difficult. You just need to reverse-engineer the conditions of a Trump loss. What are those conditions?

At the top of the list is demographics. Trump is deeply unpopular with black and Latino voters, as well as with women and young people. But Clinton is also unpopular, albeit by a smaller magnitude. Given two unpopular candidates, it’s possible that “popularity” just won’t matter as much, that voters will take both candidates’ worst qualities as a given and move on. In which case, both Clinton and Trump become generic nominees. And what are the prospects this year for a generic Republican nominee? Of five separate econometric models of the election, four predict a Republican win ranging from 50.9 percent of the vote to 55 percent of the two-party vote. The economy is middling, President Obama well-liked but not hugely popular, and Clinton would be a third term for Democrats. Given two generic candidates under those criteria, the presidency would go to the Republican. Say hello to President Trump.

Let’s say you don’t trust the models (they couldn’t predict Trump, after all). Then what? How would Trump win, assuming key parts of the electorate are aligned against him? The answer is easy: He wins and turns out white voters in historic numbers. Assume higher nonwhite support for the Democrat—let’s say a three-point bump among blacks and a seven-point bump among Hispanics, giving Clinton 97 percent and 80 percent support, respectively—and Trump needs 66 percent of whites to win both the popular and electoral-college vote, if turnout doesn’t change. (You can play with the numbers over at RealClearPolitics.)

It’s an extraordinary reach: an increase of nearly six points over the white share in 2012, matching Ronald Reagan’s performance in 1984. It would mean Trump persuaded millions of Democrats to switch teams, despite their wide approval for President Obama.

In other words, it’s not happening. Partisanship has a tight hold on American voting behavior, and it’s hard to imagine how Trump could break it, barring a national catastrophe. Easier to imagine is higher white turnout. If Trump could reverse the yearslong decline and bring white turnout back to its 2008 levels—74 percent—then he could win with another couple percentage points among whites, even with the high black and Latino turnout of 2008. This would give him teetering Democratic states such as New Hampshire, Pennsylvania, and Wisconsin, as well as the three largest swing states: Florida, Ohio, and Virginia. It’s a heavy lift, especially for a candidate who says he will eschew data-gathering and other quantitative methods for finding and mobilizing supporters. But it’s possible.

OK, OK. “Possible” doesn’t mean “likely,” and it’s hard to imagine a disorganized campaign exceeding Team Romney’s ability to pinpoint and bring Republican-leaning white voters to the polls. Still, with a smile from Fortuna (or whichever god of chance you prefer), Trump can win. If anything guarantees defeat for an incumbent party, it’s a recession. At the opening of the 1960 election, in early spring of that year, John F. Kennedy and Richard Nixon were neck and neck. This continued into the summer and the early fall. But by October, Kennedy had opened a small but persistent lead. He won.

It’s hard to isolate a single cause for Kennedy’s victory, but he was almost certainly helped along by the modest recession that struck in the spring and lasted until the following winter. If not for that downturn, there’s a fair chance Nixon would have become president. A sudden slowdown could have the same effect on our election. In fact, the very presence of Trump—his proximity to the most powerful office in the world—could destabilize markets and make a downturn more likely. And consider this: On average, the United States sees a recession every five years. We’re due. One is all we need for President Trump.

A terrorist attack could do it—driving voters into the arms of the authoritarian in the race—but the literature is mixed on how terrorism affects voters. It could make them more attuned to perceived outsiders—and immigrants in particular—giving Trump an advantage. It could push them toward hawkish candidates with traditional credentials, helping Clinton. Or given the candidates, it could be a wash. So let’s table this one.

There’s one last thing that could deliver the White House to Trump: a divided Democratic Party. Party unity is a prerequisite for national competition. It’s why the “Never Trump” movement fell apart after Ted Cruz left the race; a serious effort to derail the Republican nominee would guarantee a Democratic White House, because it’s almost impossible to overcome the asymmetry. In the still unlikely event that the present acrimony between Bernie Sanders and the Democratic Party becomes an outright split, Democrats risk throwing the election to Trump, through in-fighting and division. If Sanders runs as a third-party candidate, the game is over, and Democrats lose. You see this in the most recent polling. Clinton’s biggest weakness in the NBC News survey of registered voters is with Sanders’ backers who haven’t crossed the threshold to Team Clinton. If this persists, it’s dangerous. If history is any indication, however, it won’t be.

With all this said, even the most probable scenario here—that Trump and Clinton become generic candidates—is a distant long shot. They’re just too well-known for voters to treat them as interchangeable with any Republican or any Democrat. And their personal qualities mix with the fundamentals of this election—partisanship, demographics, and economic performance—to create favorable terrain for Democrats.

That’s the comforting irony of this whole exercise: Even when you try to show how Trump can win, you emphasize his uphill climb to victory. Still: It could happen.

Read more Slate coverage of the 2016 campaign.