The theory proposes that the far left and far right, rather than being polar opposites, actually curve toward each other — like the two ends of a horseshoe — sharing more in common with each other than either does with the moderate centre. It is a theory that tends to provoke strong reactions. Centrists find it vindicating. The far left and far right each find it insulting. And political theorists frequently find it too blunt an instrument to be taken seriously as academic analysis. Yet it keeps coming up — in op-eds, comment sections, and political debates. That alone makes it worth understanding properly. Whether you end up convinced by it or not, the questions horseshoe theory raises about what separates political extremes, and what they might share, are genuinely interesting ones.

Horseshoe theory has roots stretching back at least to the mid-twentieth century. The philosopher Karl Popper gestured toward something like it when discussing the structural similarities between fascism and Stalinism. The French political scientist Jean-Pierre Faye developed a more explicit version in his 1993 book Le Siècle des idéologies (published in English translation in 1996), where he observed convergences between the extreme ends of the French political spectrum. The term “horseshoe theory” itself became more widely used in Anglophone political commentary in the 2000s and 2010s.

It is worth distinguishing two versions of the claim. The stronger version is ontological: that the far left and far right share deep ideological commitments — authoritarianism, nationalism, anti-liberalism, conspiratorial thinking, a rejection of parliamentary democracy — regardless of surface-level differences in their stated goals. The weaker version is more behavioural or aesthetic: that extremist movements on both ends tend to use similar tactics, rhetoric, and organisational styles, even when their underlying ideologies differ substantially. These are distinct claims and are often conflated. The first is far more controversial than the second.

The Case For

Both historical fascism and Stalinism built single-party states, suppressed political opposition, cultivated cults of personality, and used state violence against perceived enemies. Hannah Arendt explored this at length in The Origins of Totalitarianism (1951), identifying structural parallels that cut across the left-right divide. The most jarring historical example is perhaps the Nazi-Soviet Pact of 1939, in which Hitler and Stalin — ideological arch-enemies by any account — signed a non-aggression agreement and jointly carved up Poland. It did not last, but the episode is hard to explain if the two regimes had nothing in common.

One of the most striking characteristics of far-left and far-right movements is their shared hostility toward liberal democracy. This surfaces in contemporary politics too. Opposition to globalisation comes from both ends: the left frames it as corporate exploitation, the right as a threat to national sovereignty — but the practical policy positions, scepticism of free trade agreements and hostility to international institutions, end up looking very similar. The same is true of anti-NATO and anti-interventionist foreign policy, where figures from opposite ends of the spectrum sometimes find themselves using near-identical rhetoric.

A striking example is the discourse around Israel and Palestine. Support for the Palestinian cause is conventionally associated with the left, while the right has historically aligned with Israel — yet on the fringes, this breaks down in a revealing way. Elements of the far right express sympathy for Palestine not out of concern for Palestinian rights, but driven by antisemitic conspiratorial thinking: the belief that Jewish people exercise disproportionate control over global finance, media, and governments. Certain corners of the far left arrive at a superficially similar position through different language — replacing “Jews” with “Zionists” in ways that critics argue function as thin rhetorical cover for the same underlying prejudice.

Some analysts point to the European far right’s adoption of welfare chauvinism — generous state provisions for native-born citizens, excluding immigrants — as a direct appropriation of traditionally left-wing economic policy. More recently, figures like Tucker Carlson and Glenn Greenwald, one broadly associated with the right and the other with the left, have developed overlapping audiences drawn together by shared scepticism of mainstream institutions and US foreign policy, despite coming from very different political traditions.

The Case Against

The theory has also attracted substantial criticism, and those objections deserve to be taken seriously. The most common is that horseshoe theory papers over profound ideological distinctions: a communist and a fascist may both oppose liberal capitalism, but for entirely different reasons, with entirely different visions of the future. Treating their anti-liberalism as equivalent ignores what each movement actually believes and wants.

The theory also implicitly places the moderate centre as the rational norm from which both extremes deviate. Critics argue this is a self-serving framing that delegitimises radical critique without engaging with its substance — that horseshoe theory functions less as analysis and more as centrist ideology. The fact that two movements use similar tactics does not mean their goals are equivalent.

It must also be noted that while Soviet and Nazi governance shared structural features, they were in direct, violent conflict with each other. The far right and far left have more often been bitter enemies than secret allies — which is difficult to explain if they are fundamentally the same.

Is It Useful?

Horseshoe theory is probably most useful as a limited descriptive tool rather than a complete theory of politics. Used carefully, it can prompt genuinely interesting questions: why do movements with opposing goals sometimes converge on similar methods? Used carelessly, it becomes a rhetorical shortcut — a way for centrists to dismiss any politics that departs from the mainstream by associating it with its mirror image on the other end of the spectrum.

It is not a complete account of politics, and it carries ideological assumptions that deserve scrutiny. The political spectrum is not a straight line — but it is probably not a horseshoe either. The truth, as usual, is messier than the diagram.