Today's youth gangs are an international problem. Montgomery County Executive Douglas Duncan should be congratulated for recognizing its complexity and traveling to El Salvador to exchange information with local officials. His trip might have included Mexico, Guatemala, and Honduras as those countries are affected too. 

Tough new laws may be popular with politicians. But research shows law enforcement can reduce crime without new laws that threaten civil liberties, by focusing on serious repeat offenders and building community partnerships. 

The gangs are the Calle 18 and Mara Salvatrucha or MS-13 that appeared in Los Angeles after large migrations from Mexico and Central America in the 1970s and 1980s. Following deportations of some members in the 1990s, offshoots sprouted in home countries that sent new recruits and deportees back through America's porous southwest border. 

Reorganized police forces in El Salvador and Guatemala were barely able to control rampant delinquency after those countries' civil wars. Honduras had no conflict, but job-seekers who got in trouble in America were returned to a country with rudimentary law enforcement. In Mexico, deportees took on poorly trained and corrupt police. Meanwhile, Colombian drug traffickers moved in to exploit gangster collaborators. 

After free elections brought peace to Nicaragua in 1990 and negotiated settlements ended other conflicts, U.S. policymakers cut support for justice reforms and police training believing peace and democracy had been won. Yet, the U.S. Immigration and Naturalization Service kept deporting an average of 4,000 and 5,000 migrants a year to El Salvador, Guatemala, and Honduras. Roughly a third had criminal records and spent time in American prisons, official data show. 

There has been an 800 percent increase since 1970 in the number of U.S. cities reporting gang problems. Authorities say gangs are active in 21 of 31 Mexican states. Officials guess Central America has 150,000 to 300,000 gang members. 

Elsewhere in the hemisphere -- like Brazil and Jamaica -- gangs are growing. Expanding populations and poverty have combined with modern transportation and communications to make them more mobile and lethal and no longer mere nuisances. They now are involved in assaults, robberies, murder, extortion, as well as drugs, arms and human trafficking. 

A decade ago, the United Nations Children's Fund estimated Latin America had about 40 million street children. That statistic and the fact nearly half of the region's inhabitants live below the $2-a-day poverty line warn of troubles to come. 

Migrants from these countries seek jobs and safety in the United States. Most work hard and become law-abiding residents or citizens. But a few slip through the cracks in transient, unstable neighborhoods -- often unable to look after their children while working multiple jobs. Studies show youth in those circumstances are at least 3 times likelier to join gangs seeking identity, socialization and self-esteem. 

Increasing migrant flows over porous borders, deportations and improved transportation and communication have led to systemic growth of transnational gangs in North America. This multifaceted problem requires a more comprehensive solution than tougher laws. To deny time and space for gangs in the United States, policymakers should: 

Promote stable neighborhoods through collaboration among federal and local law enforcement as well as community leaders to minimize characteristics that induce delinquency. 

Reduce illegal immigration by simplifying procedures to become legal workers while strengthening border controls to filter out undocumented migrants. 

Promote private-public partnerships to expand youth activities that encourage integration, competition and self-fulfillment. 

To curb transnational mayhem, U.S. policymakers should encourage Latin American neighbors to: 

Make economic reforms that establish property rights, promote entrepreneurship and the growth of new industry to boost employment. 

Strengthen the rule of law through police and justice reforms. 

Adopt family-friendly policies that improve education and help keep working families together. 

Cooperate among partner countries to share intelligence on gangs, collaborate on preparing deportees for life in nations of origin and help strengthen borders by increased training of law enforcement and immigration personnel. 

Municipal diplomacy by the Montgomery County executive and others is on the right track. Besides law enforcement, antigang efforts should focus on the systems and factors that feed gang growth, and help our Latin American neighbors to do the same.

Stephen Johnson and David B. Muhlhausen are senior policy analysts at The Heritage Foundation.