Last week, Rep. Alexandria Ocasio-Cortez (D-N.Y.) helped introduce a joint resolution for the United States to declare a “climate emergency,” a move to support her Green New Deal legislation. The same day, she also tweeted about the joys of growing her own food and issued a plea to bring back “victory gardens,” invoking the World War II-era effort by ordinary Americans to grow their own food.

Internet progressives lauded the tweet, which was unsurprising given that many others on the left see victory gardens as a force to advance their goals: Green America’s Climate Victory Gardens campaign instructs readers, “Planting a garden has the power to change the world.” Activists across the nation regularly invoke urban gardening as a panacea for tackling a range of issues, including the obesity crisis, food apartheid, economic inequality and climate change.

But by touting victory gardens, Ocasio-Cortez may have undermined her broader political agenda, especially the Green New Deal.

That’s because urban gardening is a bootstraps solution that puts the onus for a sustainable world order and good health on the individual. In reality, however, structural and institutional reform are necessary to achieve those goals. While gardens may bloom and fade with the seasons of public sentiment, government-supported agricultural systems will survive any changes of weather, even war. That’s the lesson of the New Deal and the World War II victory gardens remembered so fondly today.

The New Deal fundamentally reorganized U.S. agriculture in the aftermath of severe ecological and social devastation. Colossal amounts of precious topsoil were blown away in the Dust Bowl and lost to the Mississippi and other rivers thanks to exploitative and unsustainable practices, both cultural and agricultural. “Poor land makes poor people. Poor people make poor land,” the 1938 film “The River” explained.

The New Deal sought to improve both people and the land they worked, providing economic security to farmers, working to eliminate sharecropping and coordinating a national food supply as never before to ensure the health of all.

In the early 1940s, as the United States marshaled its resources to fight the Axis, many of the New Deal programs most focused on these goals — such as the cooperative land-use planning initiative — were dismantled. Yet the basic restructuring of the national political economy remained. A new system of agricultural subsidy, price supports for major commodity crops, and incentives for the adaptation of new technologies and inputs was even strengthened during the war.

The war also inaugurated the victory garden movement, as civilians eagerly sought ways to contribute to the war effort. A primary function of the program was to relieve farmers of the burden of feeding average Americans so that they could grow more crops for wartime use. Amazingly, at its peak in 1943, over two-thirds of U.S. households grew their own food, producing over 80 billion pounds of food, or 40 percent of the fresh produce eaten by U.S. residents that year.

Though it had Agriculture Department support, the victory garden campaign reached its height through the efforts of the National Victory Garden Institute, a coalition of corporate magnates and titans of industry. Under their patriotic but self-interested leadership, the victory garden movement sought to influence consumer preference.

Ads encouraged families that bought Green Giant canned peas in the 1930s, for example, to imitate the company’s vegetable growing operations and eat homegrown fare in wartime — before returning to Green Giant frozen peas after the war. Green Giant and other companies banked on the fact that after a few years of laboring in the sun after 48-hour workweeks, the extra work of washing and preserving while contending with scattered bad fortune and pestilence would deter many young gardeners from maintaining their efforts after the war’s end.

This sense of backyard gardening as a temporary idea, one that mimicked favored brands, made returning to packaged goods not only logical but actively desirable: Why imitate the professionals when you could let them do the job? As a result, the golden age of prepared and packaged foods arose in the wake of the greatest local-food movement in U.S. history.

As successful as victory gardens were, therefore, the movement was quickly and eagerly abandoned as national circumstances changed.

The Green New Deal, despite marked differences from its namesake, again seeks to combine social and economic-environmental problem-solving. It envisions tackling income inequality and climate change at the same time.

But it also makes a major mistake by failing to focus on agriculture — and ignoring the history of the transition from the New Deal to victory gardens to the golden age of packaged foods.

Major organizations such as the Farm Bureau and the National Farmers Union, giants of the private sector such as Monsanto and Bayer, and the market forces conditioned by current government policy have driven the immense carbon footprint of world agriculture. Alone, its emissions are sufficient to create a two-degree Celsius rise in global temperatures, even as millions go hungry worldwide.

Individuals cannot overcome the effect of these systems. Only policy changes can do that.

A successful Green New Deal needs not only to add sustainable food production but to transform the existing, destructive, agricultural status quo. Today, agriculture is dominated by agribusinesses and driven by profit, not by sustainability. But the future of agriculture must be an economically, ecologically and socially diverse landscape. Everyone who helps produce food should be paid fairly for their labor, and agriculture should be the environmental steward of the over 40 percent of U.S. land devoted to farming.

When Ocasio-Cortez suggested victory gardens, she undermined this larger project. The lesson of victory gardens is that such movements are ephemeral, subject to the whims of consumers, the power of advertising and the needs of the moment. Given the dominance of big agriculture today, gardening won’t tackle either our environmental problems or the inequities of food access across the nation.

While gardening is a good way for individuals to advance various environmental causes and enrich their lives, it is no substitute for a broader — sustainable — platform of change, one that can be brought about only by a reorganization of our agricultural political economy. Only such efforts can create a lasting agricultural system that works for the health of the people and the planet.