Lisa Franchetti is trying to break a paradigm. Admiral Franchetti is the newish chief of naval operations (CNO), or seniormost uniformed U.S. naval officer. What she says matters. Judging from her just-released “Navigation Plan,” or policy directive to the U.S. Navy, the CNO has come to believe that the Navy’s strategy, operational doctrine, and fleet design have fallen behind discomfiting new realities. Realities such as a domineering China that brandishes the armed might to make its weight felt throughout the Western Pacific. And she’s right to be disquieted.

To prosper the service must come to terms with the new normal. No longer is U.S. maritime supremacy a given. It has to be fought for—and against daunting odds.

Adapting to new times means learning to play defense. The Navigation Plan designates “nontraditional sea denial” as one of nine “key capabilities” needed to get the U.S. Navy ready for war by 2027, the deadline set by CNO Franchetti. Sea denial is a strategy of the weaker combatant. Shifting toward it portends wrenching cultural change for the U.S. Navy, a fighting force steeped in the lore of offense at sea. No one—not even the biggest of bosses—can simply ordain that an institution with a proud history of commanding the sea reorient its fleet design and operational methods toward denying a stronger antagonist maritime command.

Bureaucratic politics doesn’t work that way.

The CNO may find that instituting what amounts to a cultural revolution in the service is easier said than done. That’s because bureaucratic institutions are like machines. They exist to mass-produce the same repertoire of outputs over and over again. With machinelike efficiency come ingrained worldviews—attitudes that resist being modified when the times and circumstances change around the organization. Worldviews are stubborn things. They tend to persist even after the need to change course becomes plain. In short, bureaucracies do not readily reinvent themselves even when top leadership mandates change.

In fact, it often takes a trauma to shatter prevailing practices and habits of mind, sentiment, and deed—compelling the people constituting the organization to revise their practices to fit new circumstances. It takes a Pearl Harbor, or a 9/11.

It’s easy to lampoon bureaucracy for being ungainly and slow. Oftentimes it is. But something more basic and more human is at work here. MIT philosopher of science Thomas Kuhn saw similar dynamics at work in the scientific community six-plus decades ago. Kuhn surveyed the history of scientific revolutions in an effort to determine why and how they transpired. Past philosophers, most notably the Austrian Karl Popper, regarded scientific progress as an orderly process whereby investigators proposed hypotheses about the natural world, then tried to “falsify” or disprove them. They accepted hypotheses that couldn’t be disproved, discarded false hypotheses, or amended partially valid hypotheses until they could withstand falsification.

A proposition that survived the vetting process stood—provisionally—until and unless someone came along to debunk it with new information or insight. It achieved the status of a theory.

Now, Popper’s method would prevail in an ideal world populated by purely rational beings. But Kuhn saw scientific progress as far more fitful. He maintained that knowledge advanced less through the scientific method than through a political process—and politics by its nature is a messy affair. How did this work? Well, Kuhn contended that a theory that seemed to explain an important aspect of the natural world would attract followers. Researchers would become invested in it. Ultimately a popular theory would calcify into a paradigm, or hegemonic school of thought within the field.

Few would dispute it.

Nor would it be easy to do so. Career incentives—promotions, tenure, grants, professional accolades—rewarded those who adhered to the paradigm. Self-interest gave adherents a personal stake in the paradigm. They defended it fiercely, even if “anomalies” began to emerge between what the theory predicted and what actually happened in the natural world. These self-appointed gatekeepers adjusted the theory around the margins to explain away anomalies.

Sometimes gatekeepers stifled would-be gatecrashers. Think about the seventeenth-century church fathers who convicted Galileo Galilei of heresy for endorsing the Copernican revolution in astronomy. They insisted that the solar system rotated around the earth, long after the evidence came to suggest a heliocentric cosmos. Custodians of a paradigm tend to cling to a paradigm until the anomalies become so glaring that no reasonable person can defend it any longer. Then it collapses, giving away to a contending theory that fits observed reality better.

At that point what Kuhn calls a “paradigm shift” has occurred. These are seismic events.

Any bureaucratic institution like the U.S. Navy has a paradigm of its own that purports to explain how its operating environment works and how the institution should conduct business in it. And a bureaucracy wields the authority to enforce the reigning paradigm, transcribing it not just into career incentives and penalties for members of the organization but into doctrine—into the very fabric of how the organization interprets its mission. If Thomas Kuhn thought revolutions were tough to bring about in scientific research, a largely decentralized enterprise, he should have tried reinventing a bureaucratic institution set in its ways.

Back to the U.S. Navy and China. Over the past three decades PLA commanders and weaponeers have merged seagoing and shore-based weaponry into a dense thicket of anti-access and area-denial defenses. In other words, China’s People’s Liberation Army (PLA) can increasingly set the terms of U.S. entry into the Western Pacific while hampering the ability of U.S. forces already forward-deployed to the region to maneuver to scenes of confrontation or battle. PLA commanders also tend to husband their forces close to home, whereas U.S. joint forces are scattered across the globe on various errands.

Not just anti-access defenses but the weight of brute numbers favor China.

This turn of events throws a severe kink into U.S. maritime strategy, predicated as it is on a swift buildup of offensive combat power at the time and place of battle in sufficient measure to win a quick victory over rival naval forces. This paradigm has been in place since the collapse of the Soviet Union. Sea-service magnates, including U.S. Navy and Marine Corps leadership, codified the post-Cold War paradigm in such directives as “. . .From the Sea” (1992), which in effect proclaimed that Western navies ruled the sea by right now that the Soviet Navy lay rusting at its moorings. The services could assume away great-power opposition to their control of the sea and turn their attention to projecting power from the offshore safe haven that was the world’s oceans and seas. Skills and hardware necessary for sea combat went on the back burner—creating opportunity for ambitious newcomers like Communist China.

Nor was “. . .From the Sea” momentary bombast from a triumphant force. As recently as 2007, the sea services issued a Maritime Strategy vowing to seize “local sea control” of any body of water on planet Earth as need be—with allies, preferably, but alone if necessary.

Taking maritime mastery for granted is the old, outdated paradigm. Like the Ptolemaic geocentric model of the heavens, it sufficed for some time. But the strategic seascape has changed around the U.S. Navy. To borrow from Kuhn, anomalies now abound between the paradigm and the observed reality of a musclebound China. It is less and less plausible that the U.S. Navy, fellow joint forces, and allied forces can bid for command of the sea on day one of a Western Pacific conflict. Instead U.S. and friendly commanders must learn to play defense.

They need to engrave a new ethos on the bureaucracy, replacing the old paradigm with one fit for the times.

Strategic defense is not defeatism, by the way. Properly executed, sea denial is a prelude to strategic offense that culminates in eventual victory, probably defined as crippling PLA fighting forces to the extent that Beijing can no longer menace China’s neighbors. In the interim, though, the new paradigm means balking China’s military and political aims until such time as U.S. and allied forces can amass enough combat power to defeat the PLA. Defensive strategy can accomplish a lot. After all, China can accomplish few of its goals in the Taiwan Strait or China seas without sea command. It can bombard Taiwan from the air and inflict enormous damage.

But without control of pivotal seaways it cannot impose an effective blockade on the island, let alone get an amphibious invasion fleet across the Strait. It cannot wrest the ground from its inhabitants. Its strategy will have been stymied.

Three other tenets of the new paradigm as I see it. One, as the Navigation Plan notes, sea denial increasingly harnesses nontraditional means to fend off more powerful fleets. That chiefly means novel technologies. This is a lesson from the Russia-Ukraine war, where Ukraine—a combatant with no navy to speak of—has driven the Russian Black Sea Fleet away from its shores through imaginative use of antiship cruise missiles and aerial and surface drones. Coastal defenders have executed nontraditional sea denial par excellence.