It is often said that the US is the world’s oldest democracy. While that is not necessarily incorrect, depending on the definition of “democracy,” it tends to obscure more than it illuminates about the reality of American life. If we start from the assumption that America has been a stable, consolidated democracy for two and a half centuries, the current political conflict seems utterly baffling: where is the anti-democratic radicalization of the Republican party – and so many million Americans – coming from all of a sudden?

Is it really plausible to assume that the people who remain united behind Donald Trump and are now openly embracing authoritarianism were fully on board with liberal democracy until recently, before they were driven rightward by the presidency of a moderately liberal politician whose sole “radicalism” consisted of being Black? That the election of a religious elderly white man who has always been a proud centrist pushed them to finally abandon their supposedly “consolidated” democratic convictions?

And how can we explain that even those Republican officials who openly stand against Trump seem unwilling to support the necessary steps to strengthen democracy? Earlier this month, Liz Cheney described Russia’s attack on Ukraine as a “reminder that democracy is fragile” and talked about her obligation “to defend our democracy” – yet she doesn’t seem overly concerned with her party’s escalating voter suppression or gerrymandering efforts. Similarly, Mitt Romney warned his audience at a private fundraiser in mid-March that “preserving liberal democracy is an extraordinary challenge” – yet he helped block legislation in the Senate that would have introduced much-needed national standards for voting rights. In general, the few Republican lawmakers in Washington who are opposing the worst excesses of Trumpian authoritarianism have been strikingly unwilling to oppose the ongoing Republican attempts to subvert democracy on the state level.

Making sense of the present political conflict requires a more precise understanding of the past and present of US democracy beyond simplistic ideas of “democracy v authoritarianism.” We should start by acknowledging what “democracy” meant in America before the civil rights legislation of the 1960s: a system that was, at least by contemporaneous comparison, fairly democratic if you happened to be a white Christian man – and something else entirely if you were not. The Reconstruction period was a notable exception to this norm. But America’s first attempt at biracial democracy immediately after the civil war was quickly drowned in ostensibly “race-neutral” laws and white reactionary violence from the mid-1870s onwards. After Reconstruction, the country was dominated for decades by a white elite consensus to not only leave the brutal apartheid regime in the south untouched, but to uphold white Christian patriarchal rule within the confines of a restricted version of democracy.

By the 1960s, however, that white male elite consensus had started to fracture and America split over the question of whether the country should extend the promise of democracy to all its citizens and finally become a functioning multiracial, pluralistic democracy. Since then, two questions have defined US history: how has the reality and practice of democracy changed? And how has modern political conservatism reacted to those shifting versions of democracy, having emerged in the middle decades of the 20th century very much in opposition to precisely those liberal, multiracial, pluralistic visions?

The 1960s civil rights legislation set in motion a process of partisan realignment and ideological sorting – ultimately uniting the forces opposing multiracial pluralism in a Republican party that has been focused almost solely on the interests and sensibilities of white conservatives. And white conservatives tend to define America – “real America” – as a predominantly white, Christian, patriarchal nation. America, to them, is supposed to be a place where traditional authority is revered and white Christian men are at the top. The overriding concern of conservatism as a political project since at least the 1950s, and thus the Republican party’s overriding concern since at least the 1970s, when conservatives became the dominating faction within the party, has been to preserve that version of “real America.” In other words, conservatives’ allegiance has never been to democratic ideals – their acceptance of democracy was always conditional and depending largely on whether would be set up in a way that allowed for the forces of multiracial pluralism to be kept in check.

But due to political, cultural, and most importantly demographic changes, the conservative political project has come under enormous pressure. As the country has become less white, less religious, and more pluralistic, the conservative hold on power has become tenuous. Nothing symbolized this threat to white dominance like the election of Barack Obama – an outrageous subversion of what reactionaries understand as America’s natural order. Obama’s presidency dramatically heightened the white conservative fear of demographic change that would supposedly be accompanied by a loss of political and cultural dominance.

Republicans understand better than anyone else: in a functioning democracy, they would have to either widen their focus beyond the interests and sensibilities of white conservatives, which they are not willing to do; or relinquish power, which they reject. They are determined to transform the political system in a way that will allow them to hold on to power without majority support, even against the explicit desire of a growing numerical majority of the electorate. It is imprecise to say that conservatives are turning their backs on democracy. Rather than suddenly going from “pro-democratic” to “anti-democratic,” they have been fairly consistent: on board with a restricted version of democracy, but determined to prevent multiracial pluralism.

But what about those within the Republican party who are publicly siding against Trump, like Liz Cheney and Adam Kinzinger in the House, or senators Mitt Romney and Lisa Murkowski, who are rejecting the Republican party’s embrace of the January 6 attack on the Capitol and the attempt to legitimize political violence? I believe their disdain for Trumpism is sincere – but so is their unwillingness to support the necessary measures to defend liberal democracy. Good on them for refusing to cross over into open authoritarianism; but defenders of multiracial, pluralistic democracy they are not.

Their actions are indicative of an important conflict that has long shaped the American right. Some parts of the right were never content with accepting the post-1960s reality and railed against what they saw as the acquiescence and appeasement of the forces of multiracial pluralism. Until recently, the established story of modern conservatism’s emergence insisted that those far-right forces had been marginalized, confined to the irrelevant fringe, by the gatekeepers of the “respectable” right. However, as the latest historical scholarship convincingly argues, rightwing extremism was never fully purged from mainstream conservatism. And after Obama was elected president, the idea that Republicans were selling out “real” America, that more drastic action was urgently needed, was spreading fast into the center of conservative politics. In this view, liberals were winning, destroying the country, and Republican appeasement was complicit.

The infamous Flight 93 essay, for instance, which the rightwing intellectual Michael Anton published shortly before the 2016 election, provides the clearest articulation of this worldview. Anton presented Hillary Clinton and the Democratic Party as a fundamental threat to America, every bit as dangerous as the terrorists who hijacked four airplanes on 11 September 2001. Anton called on the right to embrace Trumpism because Trump would be willing to go much further to stop this “un-American” threat than any of the “ordinary” Republicans who were “merely reactive” and for whom Anton had nothing but contempt. Since Trump wasn’t bound by norms, traditions, or precedents, he alone could be counted on to do whatever was necessary to fight back against “wholesale cultural and political change” – to “charge the cockpit,” in Anton’s crude analogy, like the passengers of Flight 93 who thwarted an attack on the Capitol. As Anton put it, “Trump, alone among candidates for high office in this or in the last seven (at least) cycles, has stood up to say: I want to live. I want my party to live. I want my country to live. I want my people to live.”

Democracy? Who cares about democracy when “real America” is under assault and about to be overrun by radical, “un-American” leftist forces? These are not simply the fever dreams of fringe reactionaries. People like Lauren Boebert, Marjorie Taylor Greene, and Matt Gaetz symbolize the rise of far-right extremism within the Republican party, and the widespread siege mentality on the American right is the main reason why their radicalism is widely seen as justified by fellow Republicans.

The central fault line on the right is not – and has never been – simply between democracy and authoritarianism. The crucial conflict seems to be between those like Cheney, Kinzinger, and Romney who want to uphold white Christian elite rule from within the confines of a narrowly restricted version of democracy – and those who want to pursue that goal by openly embracing authoritarianism and militant extremism. I am not suggesting that this is a distinction without a difference. It matters whether or not a democratic framework remains in place because, no matter how imperfect, it provides basic protections and some room for real democratization as well as racial and social progress. But the position Cheney, Romney, et al are trying to hold has become untenable. The days of white elite rule within a system of restricted democracy are probably over – America will either slide into authoritarianism or make the leap to multiracial, pluralistic democracy.

Public critique of Trumpism matters less than the continued de facto support for an increasingly authoritarian Republican party. The fundamental reality of American politics is that, for now, the Democratic party is the country’s sole significant (small-d) democratic party. In that way, democracy itself has become a partisan issue. It’s a reality with which every lawmaker, every institution, every voter in America has to grapple honestly.

• Thomas Zimmer is a visiting professor at Georgetown University, focused on the history of democracy and its discontents in the United States, and a Guardian US contributing opinion writer