The author says that zombies make international relations fun — not as much as a first-person-shooter game, perhaps, but certainly more than a book by Henry Kissinger.

“America is back,” declared our new president a few weeks ago. A premature claim, on the whole, but not when it comes to foreign policy.

After four years of retreat from the world stage, the U.S. is reclaiming its traditional post-World War II role as the world’s indispensable nation.

Since taking office, Joe Biden has signed orders to rejoin the Paris climate accord and the World Health Organization and to end the travel ban on citizens from several Muslim countries. He has said he wants to rejoin the Iran nuclear deal, restore diplomatic relations with the Palestinian Authority and renew a strategic arms treaty that Donald Trump nearly allowed to expire.

The new president has also appointed foreign affairs and national security officials who support a robust U.S. role in the world. Most importantly, he has made no secret of his determination to rebuild America’s tattered relationships with its allies.

We’ll need them. America is facing major global challenges: from China, North Korea, climate change, the pandemic. And, of course, zombies.

Yes, those flesh-eating ghouls are very much with us — from movies like “Zombieland” and the forthcoming “Army of the Dead,” to TV shows like “Buffy the Vampire Slayer” and “The Walking Dead” (the latter made into a movie and a video game). Also, video games like “House of the Dead” and “Call of Duty,” and books like “Abraham Lincoln: Vampire Hunter,” and “World War Z” (which inspired several cinematic and gaming spinoffs).

Lately, the undead have invaded college courses on international relations. That incursion began with Tufts University professor Daniel Drezner’s seminal 2011 book, “Theories of International Relations and Zombies.” This partly fanciful work has inspired at least 30 serious scholarly papers and is now on college reading lists around the world.

To be clear, we’re not talking here about “zombie ideas,” outdated concepts that stagger on despite being discredited. Economist Paul Krugman’s 2020 book, “Arguing with Zombies,” tried to drive a stake through the hearts of such conceptual ghouls as “Tax cuts pay for themselves,” “Experts don’t know what they’re talking about,” and “Government is the problem.” To these we should, in fairness, add “Defunding the police is a great slogan” and “Donald Trump is unelectable.”

Instead, Drezner deals with a potential catastrophe that sizable percentages of Americans tell pollsters is entirely likely: a zombie invasion. The author examines possible responses that leading schools of thought in the academic foreign relations community would advocate.

These schools include liberal internationalism, which favors the collaborative advancement of peace and democracy in the world; realism, which scoffs at such efforts in an international system so prone to anarchy and realpolitik; neoconservatism, which emphasizes the importance of U.S. military strength; and constructivism, which focuses on the social and historical roots of international behavior.

If those concepts seem a bit dry, cue the zombies. They make international relations fun — not as much as a first-person-shooter game, perhaps, but certainly more than a book by Henry Kissinger.

Not only do zombies provide a tangible focus for examining the concept of exogenous threats, but many of those real-world challenges are actually threatening to suck the brains out of the world order.

Consider the problems of climate change and global pandemics. They are related: deforestation and ever-crazier weather lead people and animals to migrate, and viruses to flourish. Also, like zombies, those two plagues cannot be negotiated with, don’t care about your feelings and are relentlessly focused on wreaking havoc.

Much the same can be said about the newest major threat to democracy in the developed world: extreme right-wing nationalism. Its adherents, like zombies, exist in their own cognitive dimension, appear impervious to fact or negotiation and use violence to satisfy their appetites.

What’s a zombie-slayer to do? In International Relations 101, as in life, there are no easy answers. Nor is there any agreement on which overall approach to global problems would be most efficacious. More globalization? More isolationism? More garlic?

Drezner is careful to give each of the competing IR schools a fair hearing. Still, it’s pretty clear which one he considers the best response to a zombie apocalypse, or any other serious threat to the world order. The winner: liberal internationalism, the coalition-building strategy that Biden seems to be pursuing.

One of the best examples of that theory’s efficacy, Drezner says, appears toward the end of the British horror comedy masterpiece “Shaun of the Dead.” As zombies are devasting a placid corner of London, our hero Shaun rallies his buddies down at the pub with a quote from, of all people, philosopher Bertrand Russell: “The only thing that can redeem mankind is cooperation.”

To which, as zombies start battering down the door, Shaun adds: “I think we all appreciate the relevance of that.”

Donald Morrison is an Eagle columnist and co-chairman of the advisory board. The opinions expressed by columnists do not necessarily reflect the views of The Berkshire Eagle.