A few years ago, a man named Mike Vilhauer was fishing near Sunset Lake, in California’s Sierra Nevada mountains. He wandered into the woods to look for bait, and promptly got lost. For the next five days, he lived off the land—drinking from a stream, sleeping in a rocky cave, eating the occasional dandelion. After Vilhauer’s rescue, national and international news outlets breathlessly described his “fight for survival,” “against the odds.”

Vilhauer’s survival seems like an impressive achievement, until you stop to consider that he was simply doing what humans did, day in and day out, for most of the last 200,000 years. Of necessity, our distant ancestors had wide-ranging survival skills: they foraged, hunted, herded, and built shelters. It’s only in the last few millennia that we have taken on increasingly specialized roles. Today, we are fry cooks and nuclear physicists, bloggers and plumbers—but few of us retain the general skills that were once a prerequisite for survival.

This is interdependence, which now defines us—as individuals, communities, and nations—as never before. Interdependence means that we don’t all have to farm, or build houses, or make semiconductors. Instead, our complex social systems rely on the division of labor and exchange of goods and services to meet human needs. When people concentrate their labors on what each does best, all of society benefits—or so said Adam Smith in 1776 at the dawn of modern economic thinking.

A few years later David Ricardo extended this idea to nations, claiming that if each country focuses its production capacity on what it does better than anyone else—exploiting their comparative advantage—all nations will be better off. Later, this thinking became a pillar of the post-World War II international order. Interdependence theory—which holds that nations that depend on each other economically are more likely to work harmoniously together—has shaped thinking in Washington for almost three-quarters of a century.

Interdependence has obvious upsides. It is wondrously efficient, as it removes the redundancies of effort involved when everyone has to, say, can their own fruit—or when every nation has to grow its own rice or mill its own steel. And interdependence has coincided with an extraordinary period of peace and prosperity in the industrialized world.

But there are downsides as well. As a society’s efforts are divided into ever more discrete tasks, each member of that society becomes ever more dependent on others for the production of social goods and, ultimately, for survival—as Mike Villhauer learned on his ill-fated fishing trip.

Interdependent societies are more connected and integrated, but they are also more fragile, more brittle, and more vulnerable to cascading failures. So while highly integrated societies can accomplish feats that no group of unspecialized laborers could dream of, they do not do so well when subjected to shocks such as earthquakes, epidemics, financial crises, and political conflict. A generation ago, such shocks generally had only local effects. But in today’s hyper-connected world, a disruption in one place can swiftly cascade across the entire planet, threatening global supplies of goods and information. That’s what happened after the Tohoku disaster in Japan in 2011, the Wall Street crash of 2008, and the SARS epidemic of 2002. Accordingly, the World Economic Forum has warned of “the prospect of rapid contagion through increasingly interconnected systems and the threat of disastrous impacts.”

If your community is tightly entwined with global markets, it is vulnerable to impacts from distant disasters. In one recent study, researchers measured the economic interdependence of 364 US metropolitan areas; they then looked at how those cities fared during the Great Recession. The researchers found that the most integrated, interdependent cities (typically also the largest cities) suffered greater drops in economic performance and took longer to recover than their less-integrated counterparts.

Interdependence can pose geopolitical threats, as well. Our economic ties to other nations expose us to potential acts of coercion and extortion by key trading partners. Two decades ago, no nation had the capacity to cut off the flow of critical materials or information to the US population. Today, a simple embargo or blockade could halt the supply of vital drugs, electronics, and financial information.

That danger is real and present. A recent RAND Corporation report, prepared for the National Intelligence Council, found that China has quietly cornered the market on raw materials that lay at the base of most high-tech manufacturing supply chains. For example, China now controls 97% of the world’s supply of rare earth elements, which are essential to manufacturing everything from iPhones to advanced military technology. That gives China extraordinary leverage over the US economy and national security. It is not difficult to imagine a scenario (a trade war; escalating tensions in the South China Sea) where such leverage would come in handy.

These dangers do not, however, warrant a wholesale retreat from interdependence. This is not an endorsement of Trumpist “build the wall” isolationism and nationalism. It would not serve us as individuals, or as a nation, to wall ourselves off from the rest of humanity in pursuit of self-sufficiency. That path could leave us isolated and friendless in a dangerous world. And it would dampen the dynamism that comes with global trade in goods and ideas.

As with any set of trade-offs, there is a sweet spot to be found—somewhere between hyper-connectedness and rigorous self-sufficiency. What might that look like?

For individuals and families, it could mean planning for inevitable disruptions—natural, social, and economic. Not by moving to a survivalist compound, but by developing small-scale, local backups for the globe-spanning systems that supply essential goods and services. Begin by considering how you would obtain the essentials—food, water, and power—if supply chains are cut off.

Often, solutions are best generated at the community level. For example, small-scale “microgrids,” powered by renewable energy, offer an increasingly viable alternative to the huge but fragile mega-grid that supplies most Americans with energy. That’s how Co-op City, a housing complex in the Bronx, kept the lights on during Superstorm Sandy in 2012.

Similarly, robust local food networks can keep food on the table in times of crisis. Though local food now accounts for a small share of American agricultural markets, that can change quickly: During World War II, Americans planted “Victory Gardens” to help the war effort and produced 40 percent of the vegetables grown in the US.

At the national level, we can work to decrease dependence on China and others for raw materials. And we can place limits on the outsourcing of key industries, while nurturing a diverse industrial base in the US. Some industries already enjoy protection from global competition; for example, the American shipbuilding industry is propped up by legislation that prevents naval warships from being built outside the US. In this and similar cases, costs to efficiency may be counterbalanced by gains in national security and economic resilience.

It won’t be easy to strike the right balance between of self-sufficiency and interdependence. But it is important to get it right. Otherwise, like Mike Vilhauer, we may find ourselves wandering in the woods, fighting for survival against the odds.