This week a friend asked whether drugrunners could damage U.S. Navy littoral combat ships (LCS) policing southern waters. My answer: absolutely. Littoral combat ships are not heavily armored ships of war. They are fragile—taking Winston Churchill’s quip about eggshells armed with hammers to extremes. Wisely or not, the U.S. Navy leadership designated speed as a key attribute of the LCS, compelling shipwrights to sacrifice rugged construction to save on weight. In fact, one LCS subclass, the Independence-class trimaran, has an all-aluminum hull with a history of hull cracking—and that’s during routine conditions. The steel-hulled Freedom-class monohull, which has logged most of the navy’s Caribbean counternarcotics missions, is scarcely more stoutly built.

    Damaging such a lightweight vessel is no great feat.

    That’s doubly true under ambient circumstances. Technology has democratized naval warfare. Oceanic strife is no longer solely an affair for great powers. It’s no longer even just for states. An ever-broader range of contenders—including substate combatants such as terrorists, brigands, and traffickers in illicit wares—now avail themselves of heavy-hitting implements of war. The lines between lawbreaking and warmaking have blurred in the process. Even narcotics cartels plying the Caribbean, Gulf, or Pacific might someday lash out with lethal effect against U.S. or Latin American ships embarked on constabulary duty.

So beware.

    But littoral combat ships aren’t the only ships under threat. Any ship of war policing the sea confronts peril nowadays. The democratization of naval warfare marks a phase change. Once upon a time, during the centuries-long age of sail, naval warfare was an exclusive pursuit. Only great powers could afford enough heavy-hitting men-of-war to inflict grave harm in high-seas contests of arms. Lesser seafaring powers could make common cause with great powers, or among themselves. Otherwise they took their lumps.

    Yet the mismatch between maritime haves and have-nots narrowed once the age of steam dawned in the late nineteenth century. The machine age brought with it not just mechanical propulsion, armored hulls, and big guns, but novel weapons technologies that could menace hulking ironclad warships if the circumstances were right.

    Perversely, technology super-empowered both the strong and the weak.

    All of a sudden, “flotilla” craft—chiefly rudimentary submarines and surface patrol craft that were small, cheap, and thus affordable in bulk—could prowl near-shore waters in large numbers. They could dish out serious firepower against “capital ships,” brawlers such as battleships and cruisers, using surreptitious underwater armaments such as torpedoes and sea mines. Weaker contenders stood little chance of sweeping oceangoing foes from the sea in pitched battles. But they could erect a stout defensive buffer along their shorelines—exacting a fearful cost from battle fleets that dared approach.

    Naval commanders saw technology turn their world upside down. No longer could they ply enemy home waters with impunity, using the sea as a safe sanctuary from which to radiate military power.

    The democratization of warfare has gone into overdrive in our lifetimes. Now as in the age of steam, weak coastal states can threaten dominant oceangoing navies that venture within reach. Mines and torpedoes remain part of the armory, but local defenders can now tap even more plentiful weaponry like anti-ship missiles and aerial, surface-skimming, and even submersible drones. The Russian Black Sea Fleet learned this lesson the hard way off the coast of Ukraine, losing its flagship and a host of lesser warships to an opponent with no navy worth the name.

    Nor are such implements available only to states. This trend has been a long time coming. A quarter-century ago, a nonstate combatant, al-Qaeda, launched my career as a columnist when a boat laden with explosives managed to come alongside the destroyer USS Cole, then moored to an offshore refueling platform in the Yemeni seaport of Aden. The Cole’s assailants blasted a gaping forty-foot-by-forty-foot hole in the destroyer’s side and slew seventeen sailors. The attack announced in news-breaking fashion that sufficiently determined militants employing imaginative weaponry and tactics could incapacitate capital ships.

    Or worse.

    Fast-forward to today, and the U.S. Navy is once again heavily engaged in Yemen’s environs. Once again, a sub-state aggressor, this time the Houthi rebel group, is the antagonist. And this time the aggressor can strike hard from afar, flinging families of anti-ship cruise and ballistic missiles, along with aerial and surface combat drones, at passing mercantile and naval shipping. Houthi attacks have scored no hits on U.S. or allied warships to date, although a missile got too close for comfort to the destroyer Gravely in the Red Sea last year. But Houthi rocketeers have pelted merchant traffic transiting the Gulf of Aden and Red Sea, carrying out over one hundred attacks since launching the anti-shipping campaign in late 2023.

    Shore-launched munitions have inflicted mild to severe damage on dozens of merchantmen and sunk two. But the strategic and political effects of the campaign reverberate far beyond the stricken hulls. Rather than pay skyrocketing insurance costs, shipping firms have taken to rerouting merchantmen around the Cape of Good Hope into the South Atlantic and points beyond. Protracted voyages consume extra fuel, impose extra wear-and-tear on equipment and crews, and ultimately raise prices for goods transported by sea.

    But the effects of the Houthi campaign are even worse than that. Attacks on the shipping lanes threaten to upend freedom of the sea, the substructure on which the international legal order of the sea—and thus the ability of trading states to transact seaborne commerce—rests. Under maritime law the sea is a common, belonging to everyone and no one. If a rebel group stands a realistic chance of repealing freedom of the sea in the Red Sea, reducing a much-trafficked body of water to no-go territory, imagine the havoc brawnier enemies of nautical freedom could wreak elsewhere on the map.

    In this brave new world, in short, what were once minor nuisances for navies are now major headaches. Of course, it is doubtful in the extreme that Latin American drug cartels could ever match the Houthi arsenal, buttressed as it is by Iranian largesse. Anti-ship cruise and ballistic missiles lie beyond the cartels’ means, at least for the time being. But unmanned vehicles of various types are within their means. These are destructive, commercially available, and cheap. It is far from unthinkable that drone-wielding drugrunners could land a punch against a littoral combat ship.

    And think about what that might do to U.S. Navy deployment patterns in embattled waters. If a U.S. vessel suffered a hit or even a close call, naval commanders might start operating farther offshore for the sake of force protection. If so, such a retreat would open up maneuver space for cartel boats hugging the coast—and boost their chances of smuggling narcotics onto American shores.

    All of which reinforces the need to tighten U.S. Navy defenses, pushing hard on developing weapons and tactics for countering drones. And to extend warships’ offensive reach, it only makes sense to field flotillas of unmanned surface vehicles able to cruise contested waters without putting ship crews in harm’s way.

    Haste!