Here’s how rickety our constitutional system has become: The fate of the 2024 election could hang on the integrity of a single Republican state senator in Nebraska.

To understand why requires getting a bit deep in the Electoral College weeds. Almost all states use a winner-take-all system to apportion their presidential electors, but Nebraska and Maine award some electors by congressional district. In 2020, Joe Biden won one of Nebraska’s five electoral votes, and Donald Trump won one elector from rural Maine. This year Kamala Harris’s clearest path to victory is to take the so-called blue wall states of Pennsylvania, Michigan and Wisconsin, plus one electoral vote in Nebraska.

One reason that both states have resisted partisan pressure to switch to winner-take-all is the assumption that if one did so, the other would as well, balancing out any Electoral College effect. But this year, Republicans waited until it was too late for Maine to change its rules before starting a push to change them in Nebraska. If they succeeded and Harris held the blue wall but lost the other swing states, there would be a tie in the Electoral College. For the first time in 200 years, the election would go to the House, where each state delegation would get one vote and Trump would almost certainly be installed as president.

So far, one man, State Senator Mike McDonnell, who defected from the Democratic Party this spring, is standing in the Republican Party’s way. We should all be grateful for his courage. But the pressure on him from his new party will be intense, and he can still change his mind in the coming weeks.

Whether or not McDonnell remains steadfast, this is a preposterous way to run a purportedly democratic superpower. The Electoral College — created in part, as the scholar Akhil Reed Amar has shown, to protect slavery — has already given us two presidents in the 21st century who lost the popular vote, and it continues to warp our politics. It is one reason Erwin Chemerinsky, the dean of the U.C. Berkeley School of Law and an eminent legal scholar, has come to despair of the Constitution he’s devoted much of his life to. “I believe that if the problems with the Constitution are not fixed — and if the country stays on its current path — we are heading to serious efforts at secession,” he writes in his bracing new book, “No Democracy Lasts Forever: How the Constitution Threatens the United States.”

Chemerinsky’s description of the way our Constitution thwarts the popular will — including through the Electoral College, the growing small-state advantage in the Senate and the rogue Supreme Court — will be familiar to readers of books like last year’s “Tyranny of the Minority” by Steven Levitsky and Daniel Ziblatt. The surprising part of his argument is his call for a new constitutional convention, which can be triggered, under the Constitution’s Article V, by a vote of two-thirds of the states.

Many on the right have long dreamed of an Article V convention, hoping to pass things like a balanced-budget amendment. Chemerinsky wants to use the process to advance changes sought by progressives. It is imperative, he writes, “that Americans begin to think of drafting a new Constitution to create a more effective, more democratic government.” Without radical reforms, he fears, the country could come undone.

Chemerinsky arrived at his somewhat despairing view of our predicament with reluctance. “What makes it painful is the underlying pessimism or the underlying sense of crisis,” he told me. “I’m by nature an optimist.”

That optimism seems to drive his belief that a country as polarized as ours is still capable of sweeping positive change. “I want to believe that if a group of men and women came together and had to draft a Constitution that they knew would have to be ratified by the country, they would come up with a better document than we have now,” said Chemerinsky. “And if they failed, if it went off the rails, it wouldn’t get approved.”

I lack his faith. My fear is that while our Constitution has become a kind of cage, it’s also the only thing holding our country’s hostile factions together. The paradox of our founding document is that it’s both an accelerant to authoritarianism and a bulwark against it. The Constitution is the reason that Trump could again become president in defiance of the wishes of the majority. But if that happens, the Constitution would be one of the few tools we have to restrain him. Given our furious divisions, I’m skeptical that we could agree on a new and better one.

But I agree with Chemerinsky that because of the deep structural flaws in our Constitution, the union is more fragile than many assume. And like him, I can easily imagine America getting to a place where the idea of breaking it up no longer seems unthinkable.

America could, of course, get lucky. For this election, McDonnell could continue to resist his party’s entreaties, or Harris could win enough Electoral College votes to make any chicanery in Nebraska moot. Eventually, Congress could enact reforms that lessen some of our system’s antidemocratic distortions. One law Chemerinsky suggests would mandate that all states allocate their electors proportionally, so that all voters, regardless of their states’ partisan leanings, have a role in choosing the president. And in time, America’s demography and its political coalitions could change in ways that might help our politics come unstuck. If Texas were to become a blue state, for example, conservatives might suddenly find themselves open to Electoral College reform.

But right now, we’re staring down yet another election in which Trump could win after losing the popular vote. Chances are he’ll have a Republican-controlled Senate, even if most people who go to the polls vote for Democrats. He’ll operate under the protection of a widely distrusted Supreme Court — the only one in any major democracy where justices have lifetime tenure — that has granted presidents broad impunity for crimes they commit in office. “The mistakes made in 1787 are haunting us in the 21st century,” writes Chemerinsky. The question is whether America is capable of fixing them before they destroy us.