Ordinary citizens play a critical role in maintaining democracy. They refuse to re-elect — at least in theory — politicians who abuse their power, break the rules and reject the outcome of elections they lose. How is it, then, that Donald Trump, who has defied these basic presumptions, stands a reasonable chance of winning a second term in 2024?Milan W. Svolik, a political scientist at Yale, anticipated this question in his 2019 paper “Polarization versus Democracy”: “Voters in democracies have at their disposal an essential instrument of democratic self-defense: elections. They can stop politicians with authoritarian ambitions by simply voting them out of office.”What might account for their failure to do so?In sharply polarized electorates, even voters who value democracy will be willing to sacrifice fair democratic competition for the sake of electing politicians who champion their interests. When punishing a leader’s authoritarian tendencies requires voting for a platform, party, or person that his supporters detest, many will find this too high a price to pay.In other words, exacerbated partisan competition “presents aspiring authoritarians with a structural opportunity: They can undermine democracy and get away with it.”Svolik and Matthew H. Graham, a postdoctoral researcher at George Washington University, expand on Svolik’s argument and its applicability to the United States. Supporters of democracy, they contend in their 2020 paper “Democracy in America? Partisanship, Polarization, and the Robustness of Support for Democracy in the United States,” can no longer rely on voters to serve as a roadblock against authoritarianism:We find the U.S. public’s viability as a democratic check to be strikingly limited: only a small fraction of Americans prioritize democratic principles in their electoral choices, and their tendency to do so is decreasing in several measures of polarization, including the strength of partisanship, policy extremism, and candidate platform divergence.Graham and Svolik cite survey data demonstrating that “Americans have a solid understanding of what democracy is and what it is not” and can “correctly distinguish real-world undemocratic practices from those that are consistent with democratic principles.”Despite this awareness, Graham and Svolik continue,only a small fraction of Americans prioritize democratic principles in their electoral choices when doing so goes against their partisan identification or favorite policies. We proposed that this is the consequence of two mechanisms: first, voters are willing to trade off democratic principles for partisan ends and second, voters employ a partisan ‘double standard’ when punishing candidates who violate democratic principles. These tendencies were exacerbated by several types of polarization, including intense partisanship, extreme policy preferences, and divergence in candidate platforms.The authors have calculated that “only 3.5 percent of voters realistically punish violations of democratic principles in one of the world’s oldest democracies.”Graham and Svolik go on:To get a sense of the real-world relevance of this implication, consider that in 2016 only 5.1 percent of U.S. House districts were won by a margin of less than 6.9 percent — the smallest margin that is necessary for violations of democratic principles to be electorally self-defeating. That share of districts was still only 15.2 percent in 2018. Put bluntly, our estimates suggest that in the vast majority of U.S. House districts, a majority-party candidate could openly violate one of the democratic principles we examined and nonetheless get away with it.Graham and Svolik tested adherence to democratic principles by asking respondents whether they would vote for a candidate who “supported a redistricting plan that gives own party 10 extra seats despite a decline in the polls”; whether a governor of one’s own party should “rule by executive order if legislators don’t cooperate”; whether a governor should “ignore unfavorable court rulings by opposite-party-appointed judges”; and whether a governor should “prosecute journalists who accuse him of misconduct without revealing sources.”“Put simply,” Graham and Svolik write, “polarization undermines the public’s ability to serve as a democratic check.”Graham and Svolik’s analysis challenges the canonical view of the role of the average voter as the enforcer of adherence to democratic principles. In their 1963 classic, “The Civic Culture: Political Attitudes and Democracy in Five Nations,” Gabriel A. Almond and Sidney Verba, political scientists at Stanford and Harvard, wrote:The inactivity of the ordinary man and his inability to influence decisions help provide the power that governmental elites need if they are to make decisions. But this maximizes only one of the contradictory goals of a democratic system. The power of elites must be kept in check. The citizen’s opposite role, as an active and influential enforcer of the responsiveness of elites, is maintained by his strong commitment to the norm of active citizenship, as well as by his perception that he can be an influential citizen.The democratic citizen, Almond and Verba continue, “is called on to pursue contradictory goals: he must be active, yet passive; involved, yet not too involved; influential, yet deferential.”Trump and his allies in the Republican Party have correctly been the focus of those seeking to identify the instigators of political disruption. As Barton Gellman wrote in his December 2021 article in The Atlantic, “Trump’s Next Coup Has Already Begun”:For more than a year now, with tacit and explicit support from their party’s national leaders, state Republican operatives have been building an apparatus of election theft. Elected officials in Arizona, Texas, Georgia, Pennsylvania, Wisconsin, Michigan, and other states have studied Donald Trump’s crusade to overturn the 2020 election. They have noted the points of failure and have taken concrete steps to avoid failure next time.In the most recent issue of The Annals of the American Academy of Political and Social Science, five political scientists, Suzanne Mettler, Robert C. Lieberman, Jamila Michener, Thomas B. Pepinsky and Kenneth M. Roberts, write:For decades, political scientists have observed key threats to democracy that have been on the rise: political polarization; conflict — incited by racism and nativism — over the boundaries of American citizenship and the civic status of those in different social groups; soaring economic inequality; and executive aggrandizement. The confluence of these threats fueled the candidacy of Donald Trump, whose election was a symptom, not a cause, of American democratic dysfunction.As president, the authors continue, “Trump exacerbated all four threats, imperiling the pillars of democracy, including free and fair elections, the rule of law, the legitimacy of opposition, and the integrity of rights.”In an earlier article, in the September 2020 issue of Foreign Affairs, “The Fragile Republic: American Democracy Has Never Faced So Many Threats All at Once,” Lieberman and Mettler argue thatfor the first time in its history, the United States faces all four threats at the same time. It is this unprecedented confluence — more than the rise to power of any particular leader — that lies behind the contemporary crisis of American democracy. The threats have grown deeply entrenched, and they will likely persist and wreak havoc for some time to come.Trump, the authors argue,has ruthlessly exploited these widening divisions to deflect attention from his administration’s poor response to the pandemic and to attack those he perceives as his personal or political enemies. Chaotic elections that have occurred during the pandemic, in Wisconsin and Georgia, for example, have underscored the heightened risk to U.S. democracy that the threats pose today. The situation is dire.How much of a danger do Trump and his allies continue to represent? I asked Pepinsky how likely anti-democratic politicians are to use democratic elections to achieve their ends. He replied by email:It is very possible — not sure how likely, but entirely possible. The G.O.P.’s rhetoric is clear about what it believes a G.O.P.-led government should be able to implement, and the party has proven repeatedly unwilling to sanction its most visible political figure for plainly illegal and undemocratic behavior. And the G.O.P. machine at the state level is mobilizing to stack electoral bureaucracies with conspiracy-curious lickspittles who would love nothing more than to refuse to certify elections won by Democrats. The threat is real.Lieberman, in turn, stressed in an email the key role of white discontent as a factor in the crisis American democracy faces:The perception among many white Americans that their status at the top of the political hierarchy is eroding is certainly a critical factor fueling the crisis of American democracy today. This is a recurring pattern in American history: when proponents of expanded and more diverse democracy gain power, those who have a stake in old hierarchies and patterns of exclusion are often willing to defy democratic norms and practices in order to stay in power.But, Lieberman continued,It’s not necessarily inevitable that those defenders of old hierarchies will find refuge in the mainstream of a major political party, which gives their aims credibility and political force. When that has happened, as with the Democrats in the 1880s and 1890s, the result has been disastrous democratic backsliding. But in the 1960s, by contrast, a coalition of northern Democrats and Republicans was able to overcome those antidemocratic forces, at least for a short time.The efforts by Republicans to take over control of elections through state laws giving local legislatures the power to overturn election results — as well as by running candidates for secretary of state who espouse the view that the 2020 election was stolen — are troubling, to say the least.Donald Moynihan, a professor of public policy at Georgetown University — and the author of “Delegitimization, Deconstruction and Control: Undermining the Administrative State” in the current issue of The Annals of the American Academy of Political and Social Science — wrote by email that he is “more worried about declines in democracy driven by formal changes in the law than by events like January 6th.”Moynihan pointed out that at 3:32 a.m. on Jan. 7 — hours after protesters incited by Trump swarmed the U.S. Capitol — a majority of House Republicansvoted not to accept the results of the last election. This represents an astonishing signal by a group of elected officials of their willingness to play procedural hardball to upend democratic outcomes. State legislatures are passing laws that constrain individual rights via democratic means, and also shifting powers in a way that can ensure Republican victories. It’s very possible to envision how newly elected state and local election officials who believe Trump’s false claims about the 2020 election would make decisions where they refuse to certify free and fair elections.It is now possible, Moynihan continued,to envisage some state legislatures using fraudulent fraud claims as an excuse to select a slate of electors consistent with their partisan interests rather than with the actual outcome of their election. This is not the most likely outcome, but it is significantly more likely than it was just a couple of years ago. The confluence of events — a close election in swing states, allegations of fraud, state legislatures stepping in to choose the winner and a Republican majority in Congress endorsing this — is an entirely plausible democratic process to nullify democracy.Partisan polarization has pushed Americans not only into mutually exclusive political parties, but also into two warring civic cultures.In a March 2022 paper, “‘Good Citizens’ in Democratic Hard Times,” Sara Wallace Goodman of the University of California, Irvine, examined the growing disagreement among voters over what the obligations of a good citizen are.Goodman compared voter attitudes on what constitutes “good citizen” norms in 2004 and in 2019. A strikingly high level of agreement between Republicans and Democrats in 2004 had nearly disappeared by 2019, according to her research:Where 15 years prior, the only difference between partisans was in helping others (and the difference was slight), we see in this second (2019) snapshot several items of disagreement. In the United States, Democrats are more likely to value associational life and respecting opinions of others as values of good citizenship. Moreover, the gap between Democrats and Republicans in “helping others” has widened significantly. For Republicans, respondents are significantly more likely to value obeying the law. This portrays a clear erosion of overlapping norms, on almost every item.In his March 2022 article “Moderation, Realignment, or Transformation? Evaluating Three Approaches to America’s Crisis of Democracy,” Lee Drutman, a senior fellow at New America and the author of “Breaking the Two-Party Doom Loop,” argues that neither moderation nor realignment is adequate to address current problems in American democracy:Only reforms that fundamentally shake up the political coalitions and electoral incentives can break the escalating two-party doom loop of hyperpartisanship that is destroying the foundations of American democracy.Drutman makes the case that moderation is futile becausein today’s politics, with national identity, racial reckoning, and democracy itself front and center in partisan conflict, it is hard to understand moderation as a middle point when no clear compromise exists on what are increasingly zero-sum issues. This is where the moderation principle falls especially short. If one party or both parties have no interest in moderation or cross-partisan compromise, would-be “moderates” cannot straddle an unbridgeable chasm.What about a realignment in which the Democratic Party regains its majority status more firmly?Drutman writes in his essay:Any future scenario in which Democrats achieve a decisive and sustainable national majority is a future in which the Republican Party is almost certain to be led by the illiberal radicals who have been gaining power within the party for years as small-l liberal Republicans have fled the party. In short, “realignment” in the form of an extended period of Democratic majority rule does not offer a clear solution. It runs up against significant structural obstacles. And the more likely it seems, the more it stands a very good chance of pushing the Republican Party into even more radical insurrectionism.In fact, Drutman’s basic argument is that “there is no feasible solution to the current crisis within the two-party system itself, given the escalating polarization and the extremist trajectory of the Republican Party.”According to Drutman, “this kind of polarization, which involves not just (or not even) policy agreement but instead deep distrust of fellow citizens, is a very typical precursor of democratic decline.” Conversely, “in more proportional systems, out-party hatreds are rarer and tend to only be directed toward extreme parties.”Drutman acknowledges the many roadblocks that face the kind of transformation to a multiparty system he proposes. He argues, however, thatthe only way to make America governable for the foreseeable future is to allow new and more fluid political coalitions. Major electoral reform may seem radical, but the challenges that the American political system faces right now — toxic polarization, a major party that is rapidly embracing illiberalism, widening economic inequalities, and a racial reckoning — are immense and will blow right through straw and sticks. Only a genuine transformation of the structures of American democracy offers a solution.Still, the relentless, insidious and secretive assaults on democracy that now permeate American culture may not be amenable to procedural solution.Gerald J. Postema of the University of North Carolina describes the current embattled climate in his June 2021 essay “Constitutional Norms — Erosion, Sabotage and Response”:The degradation has resulted not from apathy or indifference, but from hostile subversion of democratic institutions and the values that they seek to serve. The attack can be stealthy. Unlike their predecessors, contemporary aspiring authoritarians pay striking attention to the forms of law in their efforts to consolidate and entrench their power. They seek to preserve the constitutional frame while “hollowing out” its substantive content and the constraints on their power that it seeks to impose. They use various devices to achieve their anti-democratic aims. They use constitutional amendments or legislation when they can, mobilizing artificial legislative majorities or manipulating weakened courts. Often, however, the assault is less direct, if no less visible, attacking the soft underbelly of the constitutional order: the norm-governed practices that give the Constitution and institutions of government their solidity, stability and vitality.The erosion of democracy is now self-evidently a global phenomenon with exogenous and endogenous causes. A brief list from the Hague Journal of the Rule of Law gives the idea:Economic inequality; political polarization; cultural backlash against rapid social, moral and demographic change; the scapegoating of immigrants and minorities by political forces; the profound — and often negative — effects of technology on society and the political system; the rise of non-liberal alternative governance models viewed as successful …. The trend of democratic decay itself — and the means by which political and social forces are degrading liberal democracy — is rapidly changing, developing and spreading. We are trying to understand a global phenomenon as it envelops the world in real time.It’s a lot to ask voters to adjudicate everything on that list. So the question that remains is this: Is the Trump version of this phenomenon the worst we are going to get, or are there people watching and waiting in the wings who will make it much worse?The Times is committed to publishing a diversity of letters to the editor. We’d like to hear what you think about this or any of our articles. Here are some tips. And here’s our email: letters@nytimes.com.Follow The New York Times Opinion section on Facebook, Twitter (@NYTopinion) and Instagram. More