Just before COVID-19 shuttered the world, I submitted an essay to a publication. The editor kindly dismissed the essay in large part over my inclusion of one historical fact about New Zealand. I had written,

New Zealand hasn’t always been safe. Many have chosen to forget, but Aotearoa (the Maori term for the land today known as “New Zealand”) was invaded in the mid-nineteenth century. Thousands were killed in the multi-decades-long colonial wars that resulted in the Maori losing their land. The more-recent political entity known as “New Zealand” faced potential invasion in the mid-twentieth century. When the Japanese threat came, the inhabitants of New Zealand again weren’t prepared for external threats.

His reason to cut this specific paragraph and ultimately kill the piece? “I’m just not convinced that history is relevant to the present.”

I call this “The Assumption.” To paraphrase: Those nightmare scenarios are far in the distant past. They have nothing to tell us about today. Nobody would ever strike a distant country’s home population nowadays. It’ll never happen again. We in the wealthy Western world are safe at home and always will be.

Americans in particular believe The Assumption. It’s as widespread as it is dangerous and represents a flaw that’s left America vulnerable to modern threats. In the end, the real problem with homeland defense is that far too many believe the homeland’s already well defended, that “Fortress America” is locked down, when nothing could be farther from the truth.

The Assumption Came from The Paradigm

Strategists, like scientists, have certain ways of seeing the world. In 1962, Thomas Kuhn’s book, The Structure of Scientific Revolutions, observed the “research paradigm” common among communities of scholars. The paradigm of the era is a set of basic assumptions that serve as baseline starting points. They’re often so fundamental that most scientists aren’t even aware of them. They remain stable over time.

Until there’s a sustained disruption—an “accumulation of discrepancies,” as Harvard’s Sam Gershman recently described it. “Kuhn’s point,” Gershman went on, “was really that there comes a point at which the auxiliary hypotheses can no longer kind of hold back the tide of discrepancies.”

As with science more broadly, a look back over time reveals several distinct paradigms in American national defense.

The first can be called the era of free security, characterized most ably by the great historian C. Vann Woodward in his 1960 article, “The Age of Reinterpretation.” Woodward observed,

Throughout most of its history the United States has enjoyed a remarkable degree of military security, physical security from hostile attack and invasion. This security was not only remarkably effective, but it was relatively free. Free security was based on nature’s gift of three vast bodies of water interposed between this country and any other power that might constitute a serious menace to its safety…

Between the second war with England and the Second World War, the United States was blessed with a security so complete and so free that it was able virtually to do without an army and for the greater part of the period without a navy as well. Between the world war that ended in 1763 and the world wars of the twentieth century the only major military burdens placed upon the people were occasioned not by foreign threats but by domestic quarrels.

Woodward went on to point out that these “peace years” were incredibly inexpensive. He noted, “Military expenditures in the 1880’s were never over four-tenths of 1 per cent.” Not only were costs low financially, but also commitment-wise. In this era, Charles Kupchan has said America had zero formal allies of any significance.

The shock of Pearl Harbor, World War II, and the emergence of the Cold War changed everything. These were the discrepancies that changed the paradigm.

Harold Rood, writing in Proceedings in 1967, captured the essence of the new paradigm that formed the “basis of US military strategy in the 20th century.” He wrote,

The first assumption is that it is preferable to defend the United States by fighting the initial defensive battles of any war as close to the enemy’s homeland as possible, or, at least, as far away from the continental United States as possible.

And so the United States began to build fences around adversaries overseas. In 1953, military reporter Hanson Baldwin assessed the challenge was “one of balance.” The issue was to choose “between offensive and defensive implements of war,” and to get the right mix of “outpost positions overseas and continental defense.”

In hindsight, it’s clear what the US Department of Defense chose. It grew over time to over eight hundred overseas bases in more than 170 countries. The forward-basing logic made sense for the Cold War. Setting aside the pesky problem of Soviet nuclear weapons, fencing off threats overseas kept attackers at bay.

The Old Paradigm has Broken Down and so has The Assumption

New enemy arsenals have broken free of these fences.

The worst cyberattack on US critical infrastructure struck last month, threatening roughly half of all East Coast gas and jet fuel. What appears to be Russian-affiliated criminal extortion against the company that carries fuel from Texas to the Northeast had the Biden administration calling for an “all-hands-on-deck” effort to avoid a surge in oil prices. While this one appears criminal, we might also be watching what the first shots of the next war will look like.

Attacks of this size on critical infrastructure—society’s essential needs—should go to the top of the national security priority list. A quick global look finds several homelands getting hit hard nowadays. Iran struck Saudi Arabia with missiles that killed oil production for months. Russia has attacked the Ukrainian power grid, part of its doctrine to use special operations to destroy critical infrastructure targets (which often goes by the acronym “SODCIT”). The US FBI director has called Chinese cyber theft “one of the largest transfers of wealth in human history.” China appears to be following the 1999 playbook of two military officers who argued for “unrestricted warfare” against nonmilitary targets “everywhere.” And North Korea, with an economy roughly the size of Colorado Springs, can threaten the US homeland directly with strategic strikes of several sizes and shapes.

America’s adversaries have found new ways to get around old defenses. They’re largely why the 2018 National Defense Strategy acknowledged the US “homeland is no longer a sanctuary.” The commander responsible for defending America, Gen. Glen VanHerck, testified in March that enemies can now “circumvent” US defenses to “hold our homeland at risk.”

Because adversaries adapt. Germany figured its way around the static system of French defensive fortifications (the Maginot Line) in 1940. Today, modern aggressors are much nimbler. They’ve co-opted former president George W. Bush’s strategy to “fight them over there so we do not have to face them in the United States of America.” Adversaries now have the option to knock out essentials like power or water. Such leverage can force the US military to stand down overseas. Or far worse, to never even be able to leave the fort or port.

This is an enormous shift. The “Doomsday Clock” has been set the “closest it has ever been to apocalypse.” That’s not due to nuclear weapons, the total number of which is down over 80 percent from its Cold War peak. Today’s most worrisome threats are more knife than nuke. Strategic knife strikes, wielded at will on intimate homeland targets, designed to hurt, bleed, disorient, and disfigure from a distance, without the muss and fuss of nuclear weaponry.

The New Paradigm

The discrepancies have slowly filled the old paradigm’s pool with gasoline. All that remains is the spark that blows away the old thinking. Because new thinking is clearly in order when America’s so heavily invested overseas but nearly naked when it comes to homeland defense.

Such imbalance creates vulnerabilities. Like a tennis player who can’t hit backhand, or the hopeful hockey team that pulls its goalie—adversaries’ exploit imbalance. If American national security is overcommitted abroad, back doors go unguarded.

Still, some look only abroad. Seth Cropsey writes that the most “important issue facing the American military” is to “win a naval war against China.” That’s half-strategy, at best. It misses the foundation. The most important issue facing the American military is to defend home first and preserve the ability to project power overseas for contingencies like a military confrontation with China at sea. The sword’s a lot more limited if the shield can’t defend.

Without really noticing, Americans are playing a version of Pascal’s wager with national security. The seventeenth-century French philosopher Blaise Pascal pointed out that people essentially bet with their eternal souls as to whether God exists. Pascal argued that rational people should live as though God exists because a modest investment would yield great gains and avoid great losses. As he wrote, “If you gain, you gain all; if you lose, you lose nothing. Wager, then, without hesitation, that [God] is.”

American homeland defense is a similar wager, another decision made under uncertainty. An opportunity to make modest investment that might yield great gains and avoid even greater losses. Rational Americans should choose to believe adversaries actually threaten the homeland and invest accordingly.

The great strategic rebalance of the age isn’t from one theater to another. It’s not about a pivot to the Pacific, it’s not about reassuring Europeans, it’s not about more meddling in the Middle East. It’s not reapportioning scarce assets horizontally at all. It’s not about width.

It’s about depth. Rebalancing toward depth.

Strategic balance is not equivalence. It’s not taking away an “offensive” asset and adding a “defensive” one. It’s more nuanced, a balance tailored to each threat. America’s offensive and defensive forces must collaborate. Homeland defense starts in Seoul, just as American forces in South Korea depend on the US homeland to send forces forward to fight if need be. We’ll always need forward-stationed forces, even as we look to reapportion some to more directly defend the homeland.

These threats demand Americans change their thinking. This isn’t new. Gunpowder’s widespread adoption in the fifteenth and sixteenth centuries forced changes in defense architecture. “When artillery became sufficiently powerful and mobile to batter down the walls of the old style of fortification,” Tim Newark has written, “there occurred a complete change in the theory of fortifications.”

Great powers have done this before. Edward Luttwak’s classic 1976 book, The Grand Strategy of the Roman Empire, noted the Romans went through strategic adjustments over the first to third centuries CE, from initial expansion to a period of forward stationing, and then ultimately, a strategic defense in depth (that wasn’t ultimately successful). More recently, David Kilcullen argues in The Dragons and the Snakes that the forward-fighting “Western way of war has been on the wane.” He calls for the “Byzantine option,” following the model of the eastern Roman Empire, which kept on another millennium after the fall of Rome in the late fifth century. Kilcullen sees wisdom in “developing new military models,” “broadening the conception of successful strategy beyond battlefield dominance,” and “focusing on financial and societal resilience,” and argues modern US planners should follow example of the Byzantines, who maintained “an edge in key technologies, often with a defensive bent, such as fortification, siege warfare, and the fearsome incendiary weapon known as Greek Fire.”

Such rebalancing toward defense must happen again. National security starts at home now. The traditional, myopic focus that once began with Beijing and the Kremlin must now advance American interests starting from home base.

If that happens, the United States will likely reduce its overseas footprint. Unnecessary headquarters will give way to smarter positions. Funds will be freed up to invest against threats to critical infrastructure. Old bases will evolve toward a layered, intercontinental, defense in depth that mitigates and matches new threats.

The United States always had great geography, just as the Greek hero Achilles was said to possess an incredible physique. In both, such natural advantages and the self-perception of raw power created an assumption of invulnerability.

That assumption famously failed Achilles. Perhaps America will avoid the Greek’s tragedy.

Lt. Col. ML Cavanaugh, PhD, is a senior fellow with the Modern War Institute at West Point and a professor of practice with Arizona State University. He co-edited, with author Max Brooks, Winning Westeros: How Game of Thrones Explains Modern Military Conflict, from Potomac Books.

The views expressed are those of the author and do not reflect the official position of the United States Military Academy, Department of the Army, or Department of Defense.

Image credit: Airman 1st Class Krystal Ardrey, US Air Force