A wall looks different depending on where you're standing. On Oct. 26, President Bush signed legislation to build 700 miles of fence along our southern border. If it's successful, this wall will look good because it will keep people out.

But how will it look from the other side?

Recently I visited the thriving city of Mexicali, about two hours south of San Diego. It has everything you'd expect in a border city: Wal-Marts, Burger Kings, industrialization, dramatic growth and a burgeoning population.

It also shares the challenges of Mexico's other major border-crossing towns -- environmental, infrastructure and housing issues, urban planning that can't keep pace with rapid expansion, and crime.

The great Mexican border metropolises and their sister cities on the U.S. side reflect the two great truths of America's southern border in the post-NAFTA (North American Free Trade Agreement) era. The border is an economic engine generating jobs and wealth. It's also a troubling place struggling to deal with the problems that accompany the meeting place where the U.S. and Mexican economies connect.

Mexicali was hosting the first-ever joint conference of the six Mexican states straddling the U.S. land border. This Conference on Security and Competitiveness on the North American Border brought together hundreds of representatives from the public and private sector to address the many issues that Mexican border communities share in common. Many participants were enthusiastic about competitiveness and deeply concerned about security.

Yet "El Muro," the Spanish name for the border fence, was the hot topic. Mexicans are deeply upset and conflicted over the initiative.

On one hand, some blamed the United States for all the security problems. America's insatiable appetite for illegal drugs fuels a trade that breeds crime, corruption and now increasing drug abuse in Mexico. For decades American immigration quotas have been unrealistically low, making human smuggling a thriving industry. American agricultural subsidies drove many Mexican corn farmers out of business and sent them north as undocumented workers to grow subsidized U.S. corn.

On the other hand, many Mexicans are deeply ashamed that the U.S. feels compelled to wall itself off from their country because Mexico cannot address its own social and economic ills. The Mexican economy is threaded with inefficiencies and corruption that thwart the expansion of free markets and hamstring the kind of broad economic growth that can benefit everyone.

They are also ashamed that their fellow citizens have to risk death in the desert for a decent job in the United States. Even worse, many Mexicans remain frustrated at the government's ineptness at enforcing its own laws. Gullermo Zepeda, a researcher for a prominent Mexico City think tank, says only 19 percent of crimes in Mexico are reported. Only 23 percent of the crimes reported are fully investigated, a little more than half go to trial. People don't report crime because almost half believe nothing will be done. Twenty percent even fear they will be victimized by the police.

There was an unspoken belief in the administration of outgoing President Vincente Fox (to differentiate his government from authoritarian regimes of the past) that lax enforcement of the law would maintain "social peace." That formula clearly hasn't worked, particularly in border cities like Tijuana where the spread of violent crime, particularly murder and kidnapping, are alarming.

Mexicans want better answers, ones that uphold the rule of law and the opportunities of a free economy.

Remarkably, no one I spoke with questioned the right and need for the United States to safeguard the border and dramatically reduce violence and criminal activity. But what I heard reaffirms my belief that all the best answers may not be in Washington.

The states and cities that line the border have to work together to develop local solutions that compliment efforts to secure the border and at the same time facilitate legal trade and travel. This must include more effective mechanisms for creating private-public incentives for financing the infrastructure that supports border crossings, such as roads and bridges.

The infrastructure we have is inadequate. Congestion delays between San Diego County and Baja California alone already cost an estimated $6 billion and 51,000 jobs a year. And cooperation is needed on public safety, environmental and natural resource issues, particularly water.

Wall or no wall, Mexico needs local leaders who insist on the rule of law and collaborate with each other and their sister cities and states to the north, instead of more corruption and complacency.

This effort needs a sense of urgency and determination. America's patience is wearing thin. And border security without border cooperation will undermine the border economy on both sides of the wall.

James Carafano is Senior Research Fellow for National Security and Homeland Security at The Heritage Foundation and author of the new book "G.I. Ingenuity."