The left is a big, intellectually eclectic political coalition. It includes democratic socialists, social democrats, anti-imperialists, progressives of varying hues, left-liberals, pacifists, Fabians, left-populists, feminists, and many others. Realism is similarly broad. It consists of classical realists, neorealists, neo-classical realists, defensive realists, offensive realists, restrainers, offshore balancers, primacists, and many others.

In both cases the in-group distinctions are not always tidy. These two ways of thinking about the world are so capacious that their membership rolls are bound to overlap. But their incidental convergences shouldn’t be mistaken for sharing a particular telos or way of seeing the world. They’re very different projects.

Most versions of the left gain little and sacrifice much in accepting a realist epistemology

This question came to the fore recently because parts of Left Twitter have rekindled an interest in realism — if not in its substance, then at least as a rhetorical resource. Some of that interest comes on the heels of the John Mearsheimer controversy over Ukraine.  Anti-imperialists in particular have taken favorable notice of the fact that Mearsheimer’s analytical position on Russia’s invasion of Ukraine can be read as a critique of the US. 

It’s not the first time the left and realists have agreed on something. Both vehemently reject neoconservatism and military interventionism. Both vocally protested the Iraq invasion. Both see America’s alliance with Israel as a militaristic distortion of the US role in the Middle East. And both opposed the successive rounds of NATO enlargement after the Cold War. It’s also entirely possible for a person to be both a self-identified realist and a self-identified leftist. 

The policy world is filled with armchair realists who embrace a realist aesthetic that has no stable meaning

But most versions of the left gain little and sacrifice much in accepting a realist epistemology. Theories of international relations are just tools for making sense of patterns and puzzles in the world; they don’t need groupies. And it would be weird to select into one specific grossly simplified model of reality over all others as a basis for formulating policy in real life. 

Realism is also so diverse that it’s impossible to have a broad-brush claim about how leftists and realists are natural kin. Aside from which type of academic realism is in play, there’s a question of whether we’re talking about an armchair aesthetic realist or a positivist realist. The latter identify with some aspect of realist theorizing (for example, states are the only relevant unit of analysis, the international system is anarchical, and you can never be certain about the intentions of others). The policy world in particular is filled with armchair realists, people who embrace a realist aesthetic that has no stable meaning beyond paying disproportionate attention to how states wield military power. Like realism as a cloak for militarism. It’s just not very clarifying to say leftists can align with realists when the latter can be so many things.  

Yet, the ideological tensions run deeper still. Realists believe security is divisible — that my security might need to come at the expense of yours and that’s just fine with me because, shrug emoji, that’s how the world works. Most leftists view security as something that’s either indivisible or that needs to sort classes in a manner that pits workers against the wealthy. Anti-war leftists, for example, have rejected balance-of-power politics since World War One — the conceptual stock-and-trade of realist politics —and many still reject it today. The left is also divided on the merits of engaging in sphere-of-influence diplomacy; a practice that realists find natural. 

I’ve never heard a realist embrace the slogan, “No war but class war”

Realists center the state — not its classes or its people — in their analysis, and I’ve never heard a realist embrace the slogan, “No war but class war.” Similarly, what leftist would, in formulating their policy positions, systematically forsake the well-being of workers in other countries in favor of winning security in a violent, highly abstracted “great game” where progress rarely means more than improving one’s relative power position? 

Moreover, realism is among the worst intellectual resources to make the case for the goals of equality and democracy that leftists seek. There is no analytically consistent realist position on the climate crisis. Leftists not only see climate change as the foremost security concern of our time because it makes the planet less inhabitable; they recognize it as a source of large-scale structural violence that promises to worsen every form of durable inequality. And realism tends to look past the ills of neoliberalism, offering nothing but perhaps encouraging a nationalist reaction against globalization (which leftists tend to see as a trap).  

More concretely, prominent realists make arguments today that are anathema to many versions of left politics. What socialist or anti-imperialist, for example, would endorse a large US forward military presence in East Asia? Yet, this is precisely what Mearsheimer and Stephen Walt counsel today. Mearsheimer even believes the US should’ve mounted a confrontation against China decades ago rather than encouraging it to become part of the global economy. The constellation of leftist thought on China is diverse, but none of it supports anything resembling that position. 

One could rightly protest that Mearsheimer does not stand in for all realists — and that is my point. He is the most prominent realist alive, and the more we cherry-pick our realist authors, the more we’re talking about a project of great idiosyncrasy rather than one based on analytically consistent reasoning. It is just as likely to rationalize militarism as it is anti-militarism.     

Ultimately, leftists of every stripe are trying to make a world that lives up to the promise of the Enlightenment, and they want to enlist the state in that project. Realists — even those who fancy themselves optimists — tend to have a more tragic view of what’s possible, and are far more focused on preventing disastrous choices in the world as they see it. 

Leftists want to build a world better than the one that realists believe we’re all trapped in

Still, realism as a positivist theory offers a conceptual repertoire that is potentially valuable for restraining the worst impulses of US power. Leftists should (and sometimes do) make use of realist concepts — the pervasiveness of the security dilemma, the balance of power (properly understood), spheres of influence, the implications of the offense-defense balance, bandwagoning, chain-ganging, and even arguably the nuclear revolution if you want to stretch what counts as realism. But selectively drawing on that repertoire — without substituting them for your own principles and analysis — is the fullest extent of realism’s value proposition to the left.I see no reason for leftists to be hostile to realists or vice versa.

Leftists should use realist concepts when it suits them. They should boost each other’s tweets. And everyone would be better if they read Hans Morgenthau. But leftists want to build a world better than the one that realists believe we’re all trapped in, and it would be entirely reasonable for realists to be wary of leftist worldmaking. Ultimately, realists and leftists may be more allies than foes, but ideological differences stand in the way of them building a better world together.

This piece originally appeared at Inkstick.