Here's What You Need to Know: The lesson of the nineteenth-century United States for twenty-first-century Brazil is this: holidays don’t last forever. Use them well.

“We have no concept of war,” confides a strategy professor at the Escola de Guerra Naval, or Brazilian Naval War College, in Rio de Janeiro—my home-away-from-home for part of 2018 and a place that unsucks, as the great Anthony Bourdain might say. Say what? Navies are fighting forces. They exist to duel rival navies. A navy that confronts no prospect of war is a force without purpose or direction. It’s rudderless.

Right?

Well, not exactly. The Marinha do Brasil, or Brazilian Navy, has more work to do than it can do. It is far from purposeless. But its work is noncombat work for the most part. That’s because Brazil has the good fortune to inhabit what Pentagon denizens call “permissive,” non-menacing strategic surroundings. The South Atlantic is free of great-power enmity. A friendly superpower navy, the U.S. Navy, furnishes a backstop should things abruptly go awry.

For the time being, anyway. The strategic setting as it exists today governs the service’s outlook. The naval leadership should cultivate what geopolitics maven Robert Kaplan terms “anxious foresight” about the future—and prepare accordingly.

Rather than gird to battle rival navies, the Brazilian Navy has long dedicated itself to constabulary duty. In effect it’s a super empowered coast guard, a combat service whose chief occupations consist of enforcing domestic law, guarding offshore natural resources from poachers, and helping Africans suppress piracy.

Concentrating on police duty makes perfect sense from Brasilia’s standpoint. If battle against high-seas foes appears far-fetched—if a navy has no concept of war but needs none—few governments would waste finite financial, material and human resources on preparing for it. The upshot: the Brazilian Navy dwells in a different strategic and mental universe from the U.S. Navy, and from any sea service that readies itself for war first and executes constabulary missions on a not-to-interfere basis with war preparations.

Countries, institutions and individuals oftentimes inhabit different mental worlds. Analyst Robert Kagan once penned a tract opining that Europeans hailed from Venus while Americans were from Mars. The United States, noted Kagan, spearheaded Europe’s defense throughout the Cold War. Europeans came to believe that security was something others supplied. They even insisted that a world ruled by international law and institutions had arrived. For them martial history had ended. If force no longer had any use, it made sense to disarm. And so they did, more or less—leaving themselves even more reliant on superpower protection.

However congenial the strategic environment appears, inhabitants of the South Atlantic should refuse to succumb to such illusions. History may yet call on Brazil to play its part in South Atlantic or hemispheric defense. It should make itself ready in intellectual and material terms.

The prospect of armed conflict is easy to overlook amid tranquil surroundings. As seagoing constables, Brazilian mariners track down non-state scourges rather than confront hostile armadas. Poachers infesting national fishing grounds constitute a particular irritant. Indeed, Brazil’s last nautical “war” was the “Lobster War” against France in the early 1960s.

The controversy broke out after French fishermen took to scooping up spiny lobsters skittering along the Brazilian continental shelf about one hundred nautical miles offshore. Brasilia mounted a show of naval force off its coasts, and Paris agreed to curtail fishing in this offshore preserve. Yet memories of the Lobster War linger—and color Brazilian maritime strategy half a century hence. They affirm the navy’s constabulary focus.

Brazilian commanders also fret about protecting natural resources underneath the seafloor. Like most coastal states, Brazil now claims an exclusive economic zone (EEZ) reaching two hundred nautical miles off its shorelines. Brasilia recently added a northerly sliver of the continental shelf, which extends still farther out to sea, to what officialdom styles the Amazônia Azul, or “Blue Amazon”—the seaward extension of the Amazon River basin.

The leadership now wants to bump out its EEZ to the south, incorporating even more marine territory into the Blue Amazon. That adds up to a lot of sea space for the Brazilian Navy to patrol. Nor are waterborne challenges all offshore. Indeed, Brazil’s navy looks inward to degree rare among navies. It’s not just a coastal or oceangoing force but a riverine force with distended inland waterways and adjacent shores to oversee. This is no small chore.

Rivers are usually a blessing. Alfred Thayer Mahan touted the Mississippi River and its tributaries for putting the interior of North America in contact with oceanic commerce. Maritime geography made it easy to ship export goods from the continental interior to foreign buyers. But the muddy Mississippi is wide and, in general, friendly to navigation. The Amazon River is no Mississippi. In some places switchbacks are so tortuous that the river is barely navigable, even for experienced riverboat skippers.

Worse, Brazilian seafarers report that the Amazon watercourse has a perverse habit of shifting from year to year. Shapeshifting terrain plays havoc with inland traffic. But because overland transport between coastal Brazil and the interior remains even more tenuous, the navy acts as the government’s humanitarian arm in the backcountry. Naval vessels commonly render medical care, for example. U.S. Navy craft seldom provide such services at home except after natural disasters—after a Hurricane Katrina or Maria. For the Marinha it’s a matter of routine.

Nor do the challenges stop with the EEZ, continental shelf, and internal waters. Despite their homeward mandate, Brazilian sailors do look beyond their maritime near abroad. But they defy expectations even when they do. Look at the map. Sea lanes transiting the region flow mainly north-south. Merchantmen and warships steam hither and yon between Atlantic seaports and the Pacific or Indian oceans, rounding Cape Horn or the Cape of Good Hope along their way.

By contrast, Brazilians’ mental map of the South Atlantic has an east-west orientation to it. They gaze mainly eastward toward Africa, where pirates prey on shipping in the Gulf of Guinea. The horizontal axis to Brazilian strategy is at right-angles to vertical shipping patterns.

It’s doubtful the contagion of maritime brigandage will spread westward across the Atlantic Ocean to afflict South America. So why—when the navy has plenty to do at home—would Brasilia go to the effort of attacking piracy at its source, and far from Brazilian coastlines? Multiple motives drive Brazil, like all societies. Accepting partial custodianship of the regional maritime order lets the Brazilian Navy portray itself as a South Atlantic force for good while preventing corsairs from distorting regional shipping lanes—and perhaps driving insurance rates so high that shipping firms reroute commercial traffic around the area.

The business of seagoing peoples is business. Suppressing lawlessness that imperils trade, commerce, and resource extraction represents sound strategic logic and helps Brasilia burnish its image as a responsible steward of South Atlantic security. What’s not to like?

Naval officialdom has made some peculiar fleet-design choices as it strives to discharge its mandate to enforce sovereignty, render social services and quash piracy. To name one, the Marinha and its political masters consider aircraft carriers a cornerstone of maritime strategy. Brasilia recently decommissioned its French-built flattop São Paulo, only to strike a bargain with British leaders to replace it with the retired amphibious carrier HMS Ocean.

Brazilian naval commanders regard flattops not as capital ships or platforms for storming hostile beaches, but as roving airfields for policing the Blue Amazon. They aren’t high-value units in carrier or amphibious expeditionary groups. They roam the sea without the familiar retinue of cruisers, destroyers, and submarines to ward off an aerial, surface, or subsurface attack. Corvettes and kindred small combatants comprise the bulk of the surface fleet.

In short, surface groups in the South Atlantic are different creatures from those in the Western Pacific or Mediterranean Sea. It’s jarring for those of us representing battle-minded navies to see pictures of a Brazilian flattop cruising with few if any sentry vessels alongside to stand guard. That’s a fleet begging to get pummeled!

Except it’s not. Thankfully.

Don’t get me wrong: aircraft carriers of humble scale do make sense for constabulary work. In fact, a flotilla of winsome “sea-control ships” resembling those envisaged for the U.S. Navy in the 1970s would fit the Marinha do Brasil’s peacetime needs better than the two fifty-thousand-ton behemoths naval proponents reportedly covet. In all likelihood a clutch of helicopters or jump jets flying from multiple light carriers dispersed offshore would provide better geographic coverage than would a bigger air wing operating from a single flight deck. After all, even the largest flight deck can only be in one place at a time.

And if Brasilia sees no need to fight for mastery of the South Atlantic, then it has little need for flattops larger than World War II fleet carriers. Why invest heavily in capital ships when lesser ones will do?

Another idiosyncrasy: the naval leadership wants a flotilla of nuclear-powered attack subs (SSNs). Again, though, it wants them for reasons alien to the U.S. Navy. (Brazil’s navy will be lucky to get so much as one attack boat any time soon. Scandal has engulfed the Brazilian presidency, throttled the nation’s GDP, and forced drastic cuts to the defense budget. Check out Netflix for a fictionalized account of this sorry affair that Brazilians are watching.)