State, locals on the ground taking security steps.

On the state and local levels, law enforcement and first responders know that cooperation is essential to saving lives. That principle is particularly relevant along the U.S.-Mexico border, where joint endeavors help to enhance security, including infrastructure protection and preparedness exercises.

"There's critical infrastructure and threats within eyesight on the Mexican side of the border," said Frank Navarette, director of the Arizona's Office of Homeland Security. "For example, there are chemical factories. It's very important to have planning in place."

While the federal authorities compile their list of targets, the states of Sonora and Arizona last year formed their own state-to-state bilateral committee to beef up infrastructure protection and disaster planning. Navarette diplomatically said the effort is complimentary to the bilateral efforts of federal agencies.

"We welcome any federal assistance. Sometimes, you know, things locally advance ahead of your federal partners," Navarette said. "It's not a dig; it's reality."

In an attempt to use off+the-shelf technology to defeat interoperability problems, Arizona DHS purchased communications switches, the ACU 1000, that links the various radio frequencies of domestic agencies and Mexican responders. The devices are stashed in sheriff's departments along the border.

The devices, and preparedness level in general, were tested in a November 2003 exercise simulating a large-scale terrorist attack in Nogales, Ariz. More than 60 of state, local and federal agencies on both sides of the border participated in the exercise.

In the simulation, a stolen chemical agent was detonated in a truck bomb at the Mariposa Port of Entry. The exercise tested the response to mass casualties and the decontamination of a hazardous agent.

Evaluators found that the ACU 1000 units worked well, despite unexpected gaps in coverage. The surge capabilities of Nogales could not handle the casualties, and hospitals in Mexico and Tucson accepted the wounded. Forms made available to Mexican nationals brought in to identify the "dead and wounded" were in English. On the whole, however, the communications systems allowed on-site leaders to deploy assets regardless of nationality.

"The Mexican city [of Nogales] is much larger, and consequently it has more first responders than the U.S. side," Navarette said. "Initially, a big asset from them was their pool of firefighters."

Despite the more advanced training and equipment for U.S. responders, the Mexican firefighters were needed to control the spread of fire from vehicle to vehicle and care for the wounded. The disparity of capabilities between Mexico and the United States sometimes can inspire cooperation, officials said.

"Our counterparts on the Mexican side are lacking in resources, so they kind of look up to us here in terms of support and training," said Santa Cruz County Sheriff Tony Estrada, whose agency took part in the exercise. "They're eager to participate."

Estrada said that law enforcement personnel from state, local and federal levels have learned to work together on a day-to-day basis, and hopes that DHS will provide the funding to further strengthen ties and upgrade communications equipment to ensure a coordinated reaction to a mass casualty event.

"We do have good relations with the Mexican government," he said. "The communication is there. The cooperation is there. We know each others' names."

Other states are reaching out as well. Texas city and state officials have met several times to discuss security and public health measures, according to Kathy Walt, Gov. Rick Perry's press secretary, but no joint exercises have resulted. California officials stated no bilateral actions have been taken.

While national politics in Mexico have been dominated by one political party until the election of Vicente Fox in 2000, individual states had been electing opposition parties since the late 1980's, which clears some institutional hurdles blocking independent state action, according to Chandler Stolp, professor at the LBJ School of Public Affairs in the University of Texas-Austin.

"[Cooperation] has been easier since Mexico has politically decentralized," Stolp noted.