Suppose Russia did follow through on its thinly veiled threat to deploy missiles and troops to Cuba or Venezuela. What kinds of missiles would Moscow deploy, and how would it deploy them for maximum strategic impact? Russia-watchers, including yours truly, have been quick to invoke the Cuban Missile Crisis precedent, which implies that Russia would station nuclear-tipped ballistic missiles of some type in the Caribbean.

Maybe. But history may not repeat itself. Russian magnates have other options than a nuclear deployment—a move Moscow might deem needlessly escalatory. They might avail themselves of conventional options.

For one, the Russian Navy might stage a squadron of warships in the Caribbean with sufficient numbers and combat power to make its weight felt along sea lanes crisscrossing the region. Such a move would confront the United States afresh with a new, old dilemma—namely, how to secure the maritime commons in the New World against powerful outsiders from the Old.

Think about the benefits this would bestow. In 1897, naval historian Captain Alfred Thayer Mahan held forth on the “Strategic Features of the Caribbean Sea and the Gulf of Mexico.” Mahan wanted to know where the U.S. Navy needed bases to guarantee access to Panama for American ships of war and merchantmen. The atlas was his trusty guide for this inquiry.

Mahan first charted sea routes to the site of the future Panama Canal from Europe and from U.S. seaports in the Gulf and on the East Coast. Next, he considered sites for island naval bases from which warships could control passage to the Isthmus. The map revealed promising strategic positions. He then evaluated candidate sites by the standards of strategic position, strength—meaning natural defenses or suitability for manmade defenses—and resources. He noticed that crucial sea lanes passed along the north, east, and west coasts of Cuba. He noticed that Cuba abounded in natural resources, suiting it to host a fleet. And in the realm of defensibility, he noticed that Cuba was a mini continent that would prove hard to blockade. Defenders could simply maneuver from harbor to harbor along interior lines, evading the blockading fleet.

Mahan adjudged Jamaica the best site for a base to command access to the canal, since it adjoined all of the crucial seaways. But since Jamaica belonged to Great Britain and its Royal Navy, Cuba was the next best alternative. And indeed, the following year the United States wrested an island empire from Spain during the Spanish-American War of 1898. Cuba was part of that empire. U.S. forces have been stationed at Guantanamo Bay, near the island’s eastern tip, ever since.

Russian strategists have doubtless taken note of Cuba’s strategic value. Indeed, Cuba would be more valuable to Moscow for making mischief at the United States’ expense today than it was to fin de siècle Washington. Jamaica may have been the best site from which to command the approaches to Panama; Mahan was not wrong. Today, though, Russian mariners would also be facing not just southward but northward toward Houston, New Orleans, Mobile, and other seaside U.S. cities on the Gulf of Mexico. Cuba overlooks the narrowish sea lane separating Havana from Key West—the sea lane that permits coastwise voyages between East Coast and Gulf Coast ports—as well as the sea lanes to its east and west, which remain the most convenient routes between the Isthmus and U.S. ports such as New Orleans, Norfolk, and Philadelphia.

This is an ideal central position for making mayhem.

In effect, the Russian Navy could threaten to interdict shipping between the U.S. Gulf and Atlantic coasts as well as shipping bound for the Pacific via the Panama Canal. If successful, Moscow would have converted Cuba into an island barrier to American nautical movement, much as the U.S. military and its partners envision using the first island chain to curtail Chinese sea and air movement.

Such a Russian maneuver could impose major trauma on the United States. During World War II, geopolitics maven Nicholas Spykman wrote that opening the Panama Canal almost literally lifted U.S. strategic culture on its axis and swiveled it southward. Accustomed to facing toward Europe, Americans now faced toward the Caribbean, the Gulf, and Panama. These waterways constituted the United States’ new portal to the Pacific Ocean, slashing thousands of miles from transoceanic voyages. After all, ships no longer needed to circumnavigate South America to swing between Atlantic and Pacific or the reverse.

A hostile fleet commanding Gulf and Caribbean sea lanes would undo the geopolitical revolution Spykman espied.

Now, this all sounds ominous, and in theory, it is. The United States asserts command of marginal waters around the Eurasian periphery; no law of world politics forbids Eurasian powers to assert command of Western Hemisphere expanses. If the Russian Navy could outmatch the U.S. Navy in American home waters, it could make maritime command a reality—barricading the U.S. Gulf Coast while blocking off the Panama Canal.

But think about it. The Russian Navy is a modest-sized force that excels in certain niche areas such as nuclear-powered submarines. To stand much chance of managing events in the Caribbean basin, Moscow would probably need to dispatch an expeditionary joint force—meaning not just naval units but also Russian Air Force warplanes and perhaps ground troops to boot—of serious heft. A rough proxy for the adequacy of such a joint force would be the U.S. Seventh Fleet, based in Japan in company with a powerful ally and backed up by the U.S. Air Force and Marine Corps.

Cuba is no Japan. Russian expeditionary forces would have no counterpart to the Japan Self-Defense Force to augment their power. They would have to do it all themselves.

To think Moscow would try to mount a deployment of such magnitude strains credulity. There appears to be strategic logic to such a move. It would tug U.S. forces southward, potentially from embattled regions like the Black Sea or the Western Pacific, and thin out U.S. forces there. And it would transform the Caribbean and Gulf from a constabulary theater, where the U.S. Coast Guard and Navy predominantly conduct counternarcotics operations, into a military theater that warrants heavy forces operating from nearby bases.

But at the same time, it would drain Russian forces from theaters of surpassing interest to Putin & Co., such as the Black Sea, Eastern Mediterranean, Baltic Sea, and North Atlantic. That would mean putting vital interests close to home at risk to play the troublemaker abroad. In the end it makes little strategic sense to hazard what matters most for the sake of something that matters less.

Which leads to a second option that delivers some of the gains minus the outsized risks and costs. Rather than up the ante by positioning nuclear weapons or a major joint force in the Western Hemisphere, Moscow might instead dispatch anti-ship cruise missiles (ASCMs) and surface-to-air missiles. In so doing, Russian magnates could radiate influence to the United States’ south while helping curb U.S. and allied influence in the Russian near abroad.

Anti-ship missiles would place shipping traversing narrow passages in jeopardy. The Russian military fields two ASCMs, the SS-27 Sizzler and the SS-N-26 Strobile, boasting combat ranges exceeding 180 statute miles. The passage skirting the Cuban west coast is the widest of the three at around 167 miles, the eastern passage is 70 miles across, and the northern passage separating Cuba from Florida is 87 miles wide. In other words, these passages lie within reach of a hypothetical Russian rocket force. Missile batteries placed at the western and eastern tips of the island and along the north coast near Havana would pose a threat U.S. leaders could not ignore.

A posture founded on conventional missiles in Cuba would not dismember the United States’ strategic position to the degree a musclebound fleet might. Shipping can detour between Puerto Rico and Santo Domingo, the island occupied by the Dominican Republic and Haiti. Or vessels can skirt southeast of Puerto Rico, past the Virgin Islands or the Antilles. Ships can access the Panama Canal from the Atlantic or Pacific—albeit at a higher cost—by steering roundabout courses to elude ship-killing Cuba-based armaments.

In all likelihood, though, seeing Russians couple geography with high technology to erect a blocking position athwart the approaches to the Gulf of Mexico would compel the U.S. military to act. The U.S. Air Force bases along the Florida Gulf Coast could become busy and intensely operational places, as could the naval air stations in Key West and Pensacola, Florida, both training bases for naval aviators. (Key West does host a variety of joint commands, but it is not a warfighting facility at present.) That would consume resources best spent elsewhere.

At the very least, a Pentagon struggling to cope with demands around the globe would have another headache to contend with.

This may all sound fanciful. But it hasn’t been that many years ago when the idea seemed outlandish that a rising great power would dredge up artificial islands in its near seas and fortify them to comprise military installations. And yet China did it in the South China Sea. Great-power competitors thrive on the outlandish. It behooves U.S. officialdom to think the unthinkable lest Washington be caught off-guard once again.