Chicago's 1893 World's Fair was a 600-acre celebration of American exceptionalism. There, amid the wonders and marvels of the modern world, the American Historical Association held its annual meeting.

Among the learned papers heard at the conference was "The Significance of the Frontier in American History," an essay by Frederick Jackson Turner that later earned a Pulitzer Prize. The Turner thesis held that life on the frontier shaped the unique American character.

Turner's reflections were said to have been inspired by a 1890 declaration from the director of the U.S. Census. The American West, the director observed, "had been so broken into by isolated bodies of settlement that there can hardly be said to be a frontier line." The frontier was gone.

Today, however, the frontier is back. But that is not a good thing. It is a problem that should worry us all. Misguided homeland security policy is making it worse.

America's frontier has shifted from the Wild West to the American heartland. In recent decades, rural communities throughout middle-America have been disappearing. Today, hundreds of counties in the Plains states house fewer than six people per square mile. By 19th-century standards, that was frontier territory.

Part of the decline in farm populations comes from the nationwide deterioration in the quality of science, technology and math education. But much of it can be traced to a crumbling rural infrastructure and gaps in the work force.

The emptying of middle America is not good for the nation. A report prepared for the G8 in April concluded that global food production would need to double by 2050 to keep the world fed. U.S. agriculture will have to be an important part of that increase. Likewise, strong, vibrant rural communities are needed to build sustainable agriculture and protect water, wildlife and other natural resources.

America's vanishing middle should be of concern to all Americans. Though agricultural workers comprise only about 2 percent of the work force and account for less than 1 percent of GDP, they are at the start of a vast and vital assembly line. American farms are part of a complex industry that processes and distributes food, energy (biofuels) and other products -- by some estimates about 20 percent of the economy.

Middle America has been emptying for some time now. But the pace is accelerating -- and homeland security policies are exacerbating the problem.

Rural communities have a tough time maintaining a quality workforce. Where illegal immigrants come in to fill the void, they place extra pressures on local coffers. Already strained communities find themselves facing rising, non-reimbursed costs for schools, hospitals, welfare services, law enforcement and incarceration.

The failure to control our borders, enforce immigration and workplace laws, and provide adequate, practical temporary worker programs to get America's farmers the workers they need is a homeland security failure that is crippling rural America.

Homeland security grants also make life in the heartland less safe. Though handing out grants is popular in Congress, these "one-time" buckets of cash to rural communities don't build sustainable programs. One group of grants shells out about $800 million a year to rural fire departments; that amounts to billions of dollars since 9/11. Yet a new study by The Heritage Foundation's Dr. David Muhlhausen found the grants "failed to reduce firefighter deaths, firefighter injuries, civilian deaths, and civilian injuries."

Worse, these grants often provided incentives for bad behavior. For example, they encouraged small communities to buy expensive, high-tech equipment they simply can't afford to man or maintain. In the end, simply throwing "security" money at small communities makes them less safe.

Homeland security is not the only part of Washington not helping. Tax laws, regulations, poor public education and rural health programs are also driving Americans off the land.

Lawmakers need to insist that government get serious about enforcing our immigration laws, help farmers get the legal> work force they need, and stop funding programs that wind up making the lives of rural Americans more expensive and less sustainable.

That's a three-point strategy to win the West -- again.

James Jay Carafano is Senior Research Fellow in national security policy at The Heritage Foundation.