Those of us following the current presidential campaign have learned one important lesson: that our predictions, whatever they may be, are likely to be wrong. Such a remarkable campaign cries out, however, for interpretation. The surprises that it has brought us seem to arise from structural changes in the American political landscape. We want to understand those changes—or at least try to understand them—so that even if we cannot predict the future, we can be at least somewhat better prepared to deal with it.

Among the most important changes with which this campaign confronts us is a transformation in our political parties. Though it may have been more obvious on the Republican side, the contests for both the Democratic and the Republican presidential nominations developed in unexpected ways. To begin with the Republicans: although it may be difficult to recall now, the single most striking fact when the presidential campaign began was the remarkable strength and depth of the Republican field. This formed a sharp contrast to the Democrats. Their only really plausible candidate seemed to be Hillary Clinton, who was not especially popular and remained dogged by accusations of scandal and corruption. Her only competitors either were unlikely alternatives—the unknown Martin O’Malley and the aged, cranky socialist Bernie Sanders—or, like Joe Biden and Elizabeth Warren, chose not to run.

The Republicans, however, had an unusually long roster of plausible candidates, including both older, experienced politicians and also young up-and-comers. Among the former were governors (or former governors) such as Jeb Bush, Rick Perry, Chris Christie, and John Kasich; among the latter were more governors—Scott Walker, Bobby Jindal—as well as several senators, such as Marco Rubio, Ted Cruz, and Rand Paul. This group could boast of impressive experience and successful records in office, and it seemed to offer also a deep pool of future talent that might shape the political scene for years to come. Republicans were entitled to feel optimistic about their prospects looking forward. Yet from all of these strong candidates, Republican primary voters managed to choose the one person lacking any experience or expertise, whose campaign initially seemed more a publicity stunt than a serious run for office: Donald Trump, who must have been as surprised as anyone when voters eventually handed him the nomination.

It would be almost unfair to hope that the Democrats would provide a similarly unlikely story, but their nominating campaign was not without unexpected drama of its own. For one of those implausible challengers to Hillary proved more formidable than could have been predicted: that aged, cranky socialist, Bernie Sanders. It is almost a fixed principle of American politics that socialists cannot succeed here. On the face of it, moreover, it would seem difficult to design a candidate who seemed less likely to appeal to young voters in particular, but that is precisely what Sanders managed to do. Before ultimately wrapping up the nomination, Clinton faced much stiffer competition from Sanders than anyone expected, and there were moments when it seemed possible that Sanders might even steal the nomination. No doubt, some of Clinton’s difficulties were due to her own unpopularity and inability to shake the taint of corruption hanging over issues like her e-mail server. But Sanders’s success was not due simply to her limited appeal; like Trump, he too managed to tap into a mood of deep dissatisfaction among American voters.

This comparison suggests something significant about the campaign: that the contests in both parties were in fact much more similar than we might initially recognize. The similarity runs deeper than the influence of voter dissatisfaction or of an insider-outsider dynamic. Rather, the nature of the disagreements within each party was similar. In each case, we witnessed a nationalist revolt against a more internationalist partisan identity. This is again more obvious in the case of Trump. His most important promises have all reflected a nationalist instinct (as reflected in his slogan, “Make America Great Again”). He has promised to rein in immigration and deport illegal aliens; he has promised greater security, based on a tough stance toward terrorism; he has questioned our international defense commitments, such as the NATO alliance; and he has criticized free trade agreements. All of these promises embody a clear determination to place America and American interests at the center of our policy, and they implicitly accuse past policy of failing to do this.

Although it may seem less evident, the Sanders insurgency—in some respects even more surprising than Trump’s—is rooted in a similar nationalist urge. To see this, we should remind ourselves of the central fact of Sanders’s political identity: that he has always been a democratic socialist. Socialism—unlike communism, which at least in theory is a stateless, global ideology—is a form of economic nationalism in which the government, either as owner or as regulator, exercises extensive control over the economy. Although Trump appeals more to cultural and Sanders to economic populism, both men claim to speak for working-class Americans who feel unrepresented by current policies. It is no accident that Sanders and Trump—unlike, say, Jeb Bush, Marco Rubio, or (until recently forced to change course by Sanders’s challenge) Hillary Clinton—have both opposed the Transatlantic Trade and Investment Partnership (TTIP), a proposed free-trade agreement between the United States and Europe.

This nationalist and populist dissatisfaction mirrors what has been going on in Europe also. There, of course, the European Union provides a convenient bogeyman for nationalist appeals. But one European country after another has seen increased support for nationalist parties that are neither straightforwardly right- nor left-wing in conventional terms, from Austria’s Freedom Party to the Alternative for Germany to the French National Front to the UK Independence Party. The same phenomenon thus appears to be transforming the party landscape across nearly all Western democracies.

What accounts for this? It is no accident, I think, that this change is sweeping the West in the wake of the increasing globalization that has occurred since the collapse of the Soviet bloc. Globalization is a difficult concept to define, but it refers to thickening cultural and economic ties that develop among states as they participate more fully in international networks of communications and trade. This process appears to be generating a new divide within Western societies, creating a world in which the upper and upper-middle classes feel more “at home” (if I may use that phrase in this context) than do middle- and working-class citizens, to say nothing of the poor. Their differing levels of “at-home-ness” derive from both economics and culture. The economic benefits of globalization extend, on balance, to entire democratic populations, since all citizens enjoy, for example, the benefits of lower prices when trade opens up new markets. (Indeed, these benefits are probably more important for lower-income citizens than for the wealthy.) But the costs of global competition are localized: competition causes a particular factory, in a particular town, to go out of business and lay off its workers. Middle- and working-class citizens feel vulnerable to these dislocations, which the better-off are less likely to suffer and more likely to navigate successfully should the need arise. Culturally, the professional classes are more likely to feel comfortable traveling and interacting with their peers in other cultures; members of the working class, by contrast, generally have more local attachments and a more parochial (a term I use without any negative connotations) cultural horizon.

Politicians and policy-makers, bureaucrats and judges all belong to the professional class, and it is therefore not surprising that they feel relatively at home in an increasingly globalized world. Nor is it surprising that the voters whom they govern feel inadequately represented—are, perhaps, inadequately represented—by these “insiders,” “elites,” or the “establishment.” (None of these terms are very helpful in my view, but all carry rhetorical weight in our political discourse.) So we see the same shift occurring in both political parties—in a slightly different key, no doubt, given the parties’ differing traditions and principles, but variations on the same theme nonetheless.

What does this portend for the future of American party politics? Since it seems unlikely that both parties will continue to function successfully if riven by internal conflict, we should expect some shifting of the ground. For example, we could imagine a third party arising—like some of the European parties mentioned earlier—and displacing one of the two existing parties by appealing to this nationalist discontent. Third parties, however, have difficulty getting a foothold in the American system—more so than in European parliamentary systems. Usually, when one does threaten to gain strength, one of the two main parties will adopt its themes and siphon off its voters.

Alternatively, we could imagine “elites” from both parties, or simply their more mainstream voters, joining together in a kind of new coalition party. This too would have a European parallel of sorts, since European parties of the center-right and center-left have on occasion joined together to defeat an upstart populist party, like the Freedom Party in Austria or the National Front in France. But this too seems somewhat implausible, since it would require people to abandon strong rival identities as Republicans and Democrats.

More likely would be a decision by one of the parties deliberately to take up the nationalist banner and remake itself as a populist party in this vein, with a platform drawing on what might seem a mix of Republican and Democratic impulses: anti-immigration, anti-trade, isolationist in foreign policy, committed to preserving entitlements and the welfare state. Since this is more or less Trump’s platform, and since the Trump insurgency has actually succeeded, it is perhaps more likely that the Republicans would move in this direction than the Democrats. If either party were to do this, however, it would be cause for concern. For it would seem likely to make American electoral politics more class-based, with a party of the haves, or the winners in a globalized world, against a party of the have-nots, those who feel themselves to have lost out as a result of globalization. This would be a step backward. From Aristotle to the Federalist papers, the chief historical critique of democracy has always been that it encouraged rule by faction and allowed the many poor to oppress the few rich. The great success of American constitutionalism has been to create a middle-class democracy, in which party lines have not simply coincided with those of socio-economic class. A partisan struggle between globalization’s winners and losers would threaten to erase this achievement.

It harbors the seeds of an even more worrisome problem, however, one difficult to describe but worth sketching here briefly. Suppose that the Republicans did indeed remake themselves in Trump’s image, as a nationalist party. And suppose that the Democrats became in turn the internationalist party. What would the latter look like? We know from Trump roughly what a nationalist party platform would involve, but what exactly would an internationalist platform be? There are more ways than one to be “internationalist,” but suppose—one last supposition—that it took a cue from Trump himself, who has attempted to cast the current election as a battle between “patriots” and  “globalists.” “Globalists” are those cosmopolitan types uncomfortable with their own country and its culture, more at home with their peers in other countries, and only weakly attached to their fellow citizens. Moreover, they are often committed—this is an important subtext of Trump’s rhetoric—to what is often known these days as “global governance” or transnationalism. Global governance undermines sovereignty and downgrades the claims of the nation-state, seeking to move authority instead toward international institutions such as the European Union, the United Nations, or the International Criminal Court.

Global governance of this sort is different from, say, the internationalism of more traditional treaty-making, which preserves the independent and sovereign status of the nation-states committing themselves to an agreement. The chief difficulty with this more ambitious form of transnationalism is that it is inconsistent with the US Constitution. Under the Constitution all democratic authority is grounded in the People. It rises from below. The Constitution does not permit our sovereign authority to be handed away; it is premised on the existence of a demos that gives itself law. We, the People, retain, always, the ultimate authority to govern ourselves.

A partisan quarrel between nationalists of the Trumpian sort and globalists of this type would be a disaster. It would confront us, on the one hand, with a party that rejects the principles and practices that have served America so well over the past century, in particular commitments to trade and to the defense of freedom internationally. And it would confront us on the other hand—for perhaps the first time since the Civil War—with a party that, implicitly if not explicitly, rejects the basic constitutional order. We would have one party that was constitutional but that supported lousy policies, and another that supported better policies but was anti-constitutional. That would be a poor choice of alternatives indeed.

Such a development should also worry Christians. At the risk of oversimplification, it seems to me that any plausible Christian approach to politics must balance particularist and universalist commitments. As embodied creatures of place and time, we inhabit specific countries and have special obligations toward our fellow citizens. But as redeemed men and women with a destiny in the Kingdom of God, we also owe duties of Christian charity to persons around the globe. In different ways, the Republican and Democratic parties as they have existed in recent decades have struck a balance between these two emphases. Christians in both parties must therefore strive to recognize—and not only recognize, but address—the concerns that are driving the current wave of bipartisan nationalism, but without entirely abandoning international commitments in the process. I fear, however, that we may be facing a future in which our particularist and univeralist commitments are housed in opposing political parties, threatening to leave Christians as well as constitutionalists without a viable partisan option.

One can only hope, therefore, that the campaign and its aftermath still has other, different surprises in store for us.

Peter Meilaender is professor of political science at Houghton College.