Quotes of the Day

When the U.S. sneezes, Mexico catches a cold — so goes the old saying that is ironically being turned on its head as all eyes look south, afraid that the U.S. may be infected by what appears to be Mexican swine flu. But while public health and government officials on both sides of the border battle the outbreak, a virus of another sort is spreading across the Internet as anti-immigration groups use the imminent flu pandemic as an argument for closing the U.S.-Mexico border.

"Americans want our borders secured now more than ever," declared William Gheen, head of Americans for Legal Immigration. The North Carolina–based group is calling on the Obama Administration to shut down the southern border. "This latest in a series of health threats emanating from Mexico speaks loudly for border security, and the government's failure to respond accordingly should be a wake-up call for all Americans," Gheen said in a statement posted on the group's website. (See pictures of the Great Wall of America.)

Other groups like the California Coalition for Immigration Reform, the San Diego Minutemen and various Save Our State groups have joined the chorus, sending out a barrage of e-mails to supporters and engaging in Web chatter about the perceived threats from Mexico. The push has gained some traction in Washington, while being rejected, thus far, by the Administration. "The public needs to be aware of the serious threat of swine flu, and we need to close our borders to Mexico immediately and completely until this is resolved," New York Democratic Congressman Eric Massa, a member of the Homeland Security Committee, said earlier this week. Across the aisle, San Diego Republican Congressman Duncan Hunter suggested that all nonessential border traffic be shut down. (See pictures of the swine flu outbreak in Mexico.)

But shutting down the almost 2,000-mile-long U.S.-Mexico border would be a disaster of a different sort. While anti-immigration groups focus on the impact of illegal entrants to the country, there is little attention paid to the goods that flow both ways: wheat (vital for production of the Mexican staple, tortillas) and other food commodities head south, while assembled goods made from U.S. components head back north. In that mix are some products that could be essential if the flu spreads. Dr. Carlos del Rio, chairman of the global health department at Emory University, wrote in a CNN op-ed, "In the event of a serious flu outbreak in this country, there would be a need for mechanical-ventilator deployments to hospitals. The national stockpile has sufficient ventilators, but the necessary circuits that are needed to operate them are not produced in the United States but in Mexico, so having them come across to this country is critical for taking care of critically ill patients in the United States."

"Half of the land-borne U.S.-Mexico trade comes through Laredo," says Keith R. Phillips, a senior economist with the Federal Reserve Bank of Dallas. Much of it heads north along Interstate Highway 35, through Austin, Dallas and on through the heartland. And it's not only the land ports along the border that are conduits for trade and travelers, Phillips points out. The Port of Houston has been one of the fastest-growing ports in the country, with a significant amount of trade from Mexico, and trade also flows into inland ports like Fort Worth's Alliance Texas Logistics Park. As residents of Midland, Texas, can attest, the constant rumble of freight trains coming up from Mexico's deep water ports on the Pacific Coast is further evidence of the deep economic relationship.

Before the flu epidemic emerged, both sides of the border were feeling the economic downturn — and the ripple effect was moving farther north. Phillips says the manager of a large outlet mall in San Marcos, 200 miles north of Laredo, Texas, told him that sales were down over the Easter holiday, traditionally a popular shopping time for Mexican tourists in Texas. But that slowdown would pale beside the impact of a border shutdown. (See a video of protests against building a wall on the U.S.-Mexico border.)

The first known flu fatality on the U.S. side of the border is emblematic of the problem posed by the symbiotic relationship. The 22-month-old boy who died of the flu in a Houston hospital had flown from Mexico City to Matamoros to visit relatives across the bridge in Brownsville. Many families, Phillips points out, have one foot in both countries. Managers for Mexican industrial plants on the border often live north of the river, while workers in the plants have family ties deeper inside Mexico and frequently head south.

The border is a crossing point, not a canyon, and just a brief look at the numbers offer an idea of how busy that crossing point is. In January and February of this year, some $16 billion in exports went south from the U.S., while some $21 billion of imports came north, according to the Texas Center for Border Economy and Enterprise Development at Texas A&M International University. In Brownsville alone, in the first two months of this year, there were 297,478 legal pedestrian crossings north and 284,662 legal southbound crossings. Personal-vehicle crossings were almost double that number. Almost 4 million passenger vehicles crossed each way between Texas cities and their sister communities in Mexico in the first two months of this year, while almost half a million trucks headed south in the same period and 370,000 headed north, according to the center.

Texas Governor Rick Perry says any talk of closing the border is "premature." Meanwhile, Perry has declared a state of emergency and called on the Federal Government for support — an irony, his opponents say, given his recent comments about secession. But Perry, cognizant of the economic importance of the border and the close relationship with Mexico, appealed again to Texas pride: "As Texans always do when facing a challenge: We prepare for the worst, we pray for the best. Working together, we will get through this challenge as well." But if the demands to close the border succeed, Texas would have not only a public health challenge on its hands; it would face a disruption in trade that would send an economic tsunami into the heart of America.

See the world's most influential people in the 2009 TIME 100.

• Hilary Hylton / Austin, Texas
• Activists are using the looming pandemic to argue for closing the border. But the effect of that could be an even greater disaster