It is possible to sense relief, even guarded optimism, among US Democrats and right-thinking people everywhere. Donald Trump, the tycoon and political neophyte, who swept to the Republican nomination despite the hostility of party stalwarts, has had a bad couple of weeks, very bad, in fact.

Trump’s showing in the opinion polls has been inexorably downwards since Hillary Clinton’s triumph at the Democratic National Convention. He has reshuffled his top team for what seems the umpteenth time, and muttering can be heard to the effect that he never really wanted the job anyway. Wishful thinking even has sundry Republicans asking whether Trump might decide to make way for someone supposedly more electable.

Of course, it’s not over until it’s over. Trump’s whole campaign to date has defied the odds, and his camp insist -quite rightly – that it is very early days. The campaign proper never really begins until after Labor Day, the first Monday in September. Even then it will have two full months to run. What is more, there are legitimate questions about both the accuracy of polling and the volatility of US opinion. Americans vote on November 8. Throughout this time, the Europeans will be commenting from the margins, comparing our variegated systems with theirs, almost entirely to our advantage. US presidential campaigns, we will say, are far too long, far too expensive and borderline corrupt. Even the voting system, with its differences between states, those ancient machines that frustrate recounts and the inequalities seemingly built into the registration system will be cited as proof of our superiority. Many Americans would agree; they are some of the least sparing critics.

What Donald Trump’s unpredicted rise and, current, fall already show, however, is something we tend to neglect. What looks like a mad electoral marathon that serves no one well and costs extortionate amounts of cash is not a bad test of presidential potential. What is more or less a year-long campaign has a pace and a logic that ruthlessly exposes those who cannot make the grade.

A US election campaign has something of the medieval tournament about it. It offers a grueling series of obstacles to be surmounted and trials to be endured. Whoever wins will have proved to be equal to the task of presiding over the most powerful country in the world. And yes, by the way, it still is. The most basic requirement is stamina. Would-be presidents have to put in the time and the miles. Trump and Clinton have now been on the road more or less continuously since last autumn. They cannot be seen to flag. From September they will be crisscrossing the country, speaking at venues from vast sport stadiums to tiny parish halls, fitting in several meetings in one day. It is an intense replication of what it is like to be President of the United States. The last frantic dash, coast-to-coast, battle-ground to battle-ground is one of the ultimate in electoral challenges, and – in a close race – one of the most thrilling.

The second is the capacity to raise money; a lot of it. Like it or not, though, the role of corporate money in the United States makes the confidence of business a pre-requisite for any US president.

There are different ways to acquire it. Hillary Clinton has the benefit of her husband’s presidential network, and her own from her time as New York Senator and Secretary of State – corporate support which risks also being a liability this electoral year, because it associates her so closely with “the establishment”. George W Bush had the Bush networks and his own business ties. Donald Trump can boast – as could Michael Bloomberg – that his money is largely his own, and his business record stands for itself. Barack Obama’s biggest task eight years ago was arguably to convince corporate America that he was a winner. As the personification of the state, a US President must also be at least, on the presentational front, competent. Bill Clinton was the master communicator; he grasps at once the disposition of his audience. He makes the connection, conveys the message, wins the argument – and all with an ease that his wife has had to learn. A future president must convince, both in person and, crucially, on television – even in this time of social media. If he or she isn’t born with the ability, they acquire it over the months of campaigning.

A US presidential campaign is the longest and most demanding political stress test conducted anywhere, and it’s always in the public eye. Candidates must keep cool under pressure and cope with reversals. Personal flaws, past and present, can surface at any time. These need not be fatal, as Bill Clinton and Trump – so far – showed. It depends how the candidate handles them and how the public responds. As the polls now stand, it looks as though the voters will have the sense to reject Donald Trump. If he nonetheless prevails, however, it would be wrong to dismiss his victory as a fluke. He will have won not primarily because of money or showmanship, but because, in emerging victorious from the trials of a US presidential campaign, he will have convinced Americans that he can do the job.

We have a tradition in the United States. When you lose an election, you take the L, and you move on. It’s what John Adams did after he lost to Thomas Jefferson in the 1800 election, marking the first ever peaceful transfer of power after a bitterly contested democratic election. It’s what Samuel Tilden and Al Gore did after their respective elections, in 1876 and 2000, when they won the national popular vote but lost the tally in the Electoral College. And it’s what Richard Nixon did after losing the 1960 election in an incredibly close race with John F. Kennedy, despite evidence of fraud in Illinois and suspicions of it in Texas.

We have a great track record on this count, with one exception in our 228-year history of presidential elections. (It didn’t work out.) And we owe that track record to a set of shared norms about our political institutions. In the modern era, those norms are straightforward. We all agree in the principle of one person, one vote. We all agree that, in each state’s Electoral College, electors go to the winner of the popular vote. And for the most part, we all agree that the major parties are legitimate groupings of citizens and interests, with a legitimate claim on power should their candidates win an election.

That hedge— “for the most part”—is intentional. For the most part, we do agree that the winners are legitimate. For as much as Republicans worked to stymie Barack Obama’s presidency through unprecedented obstruction, they never sought to delegitimize the election results or argue that his wins didn’t count. At the same time, Republican lawmakers throughout the country—and especially in the South—have engaged in a project of voter suppression, animated by the barely veiled idea that some voters are more legitimate than others. They cry “fraud”—ignoring all evidence to the contrary—and suggest stolen elections. It’s corrosive and dangerous, not the least because these voter laws target black and Latino citizens in a clear echo of Jim Crow.

“Fraud” is part of the backdrop of Republican politics on the state and local level, but conspiracy theorists aside, it hasn’t bubbled up into national politics. Republican leaders opposed Obama (and Bill Clinton before him) and even challenged his authority as president. But they didn’t attack the election itself, or suggest the results were illegitimate. Enter Donald Trump.

Trump has no use for norms. He violates them at will, from relatively trivial transgressions such as his personal attacks on other presidential candidates (“Little Marco,” “low-energy” Jeb), to the worrying ones such as his habit of spreading conspiracy theories (e.g., the charge that Ted Cruz’s father helped assassinate John F. Kennedy), to the serious ones such as his calls for religious tests, his tolerance of white supremacists, and his exploitation (and occasional use) of explicit racism.

Trump’s contempt for norms has only gotten worse in the past few days, as he reacts to the Democratic National Convention—and his subsequent collapse in the polls—with rage and anger. And on Monday, he crossed one of the brightest lines in American politics, the one that deals directly with our tradition of peaceful transfer of power.

“I’m afraid the election is going to be rigged, I have to be honest,” he said to a crowd in Columbus, Ohio. He followed up on this in an interview with Fox News’ Sean Hannity. “I’m telling you, November 8th, we’d better be careful because that election is going to be rigged. And I hope the Republicans are watching closely, or it’s going to be taken away from us.”

The simple truth of American politics—and of democratic life at large—is that our institutions are only as strong as the norms around them.
This was in line with comments from Roger Stone, a longtime adviser to Trump. In a recent interview with Breitbart’s Milo Yiannopoulos, Stone said that Trump should start talking “constantly” about the chance of voter fraud and a rigged election. “He needs to say for example, today would be a perfect example: ‘I am leading in Florida. The polls all show it. If I lose Florida, we will know that there’s voter fraud.’” Stone continued in this vein. “‘If there’s voter fraud, this election will be illegitimate, the election of the winner will be illegitimate, we will have a constitutional crisis, widespread civil disobedience, and the government will no longer be the government.’”

From here, Stone’s language gets ominous. “If you can’t have an honest election, nothing else counts,” he said. “The government will be shut down if they attempt to steal this and swear Hillary in. No, we will not stand for it. We will not stand for it,” Stone said, promising a “bloodbath” of “civil disobedience.”

You could say that there’s nothing new here, that earlier Republicans have brought similar rhetoric to the table, and thus that this—if there’s a difference at all—is one of degree and not of kind. In the aftermath of 1960, allies of Nixon alleged fraud. And again, in the wake of Obama’s 2012 victory, Alex Jones and other conspiratorial figures obsessed over the idea that the election was stolen. But this elides fine details. For instance, neither Nixon’s allies nor Alex Jones was a candidate for the presidency of the United States. This world we’re in, in which a major party campaign maligns the election as rigged well before the fact and promises a proverbial “bloodbath” in the event of defeat, is a new one.

It’s possible that this is just impulsive nonsense from unscrupulous men with no bearing on the election. But I wouldn’t dismiss it. Presidential nominees matter. What they say matters. Trump is a major party leader in an age of rigid partisanship. Not only has this bound reluctant lawmaker to his campaign, but it’s given him a definite floor for votes in the general election. If he loses, it won’t be a landslide. It might even be close. Which makes this language dangerous.

A Donald Trump who accuses the Democratic campaign of fraud—who says Hillary stole the election from him—is one who has allies and enablers within his party. It’s one who has an audience with millions of voters, primed to believe in an epidemic of fraud and stolen elections, where “fraud” often means black and Latino voting.

What happens if Trump loses the election, and he claims fraud? What happens when hundreds of thousands of his most loyal followers—fed on a diet of anger and rage—convince themselves that the race was stolen from their tribune? The simple truth of American politics—and of democratic life at large—is that our institutions are only as strong as the norms around them. Those norms are the superstructure of democracy; they help us navigate conflict and mediate change. When they’re violated, either by unaccountable elites or by reckless politicians, we suffer. And right now, one of those elites is undermining them for the sake of his own ego, stoking fear and distrust just so he can lose the election without losing face.