Violence, poverty, unemployment and President Obama’s immigration policy have all been blamed for the massive arrival of unaccompanied children from Central America at the U.S. southern border.

Some immigration experts and advocates suggest another factor: U.S. policies of the 1990s and 2000s that deported thousands of gang members back to Central America.

At the time, authorities were attempting to root out Latino gang violence in American cities. But instead of dispersing, the gangs took new root in Central America, abetted by the push of drug-trafficking routes into Central America from Mexico. The gangs grew more ruthless and expanded into international drug trade and other crimes, leading to escalating violence in Honduras, Guatemala and El Salvador.

Critics of proposals to deport the new crop of youths warn that the United States risks making the same mistake twice, accelerating violence over the border by condemning those fleeing the gang explosion to become either gang members or victims.

“Those who are returned now will face much worse conditions than those who were sent back in the 1990s. There is more violence, more poverty and less opportunity,” José Guadalupe Ruelas, director of the Casa Alianza youth rehabilitation program in Honduras, said on a recent visit to Washington. “In the past, when we asked deported children what their motive was for fleeing, they would say being poor or wanting to be with their families. Now the great majority say it is because of violence.”

In this April 14 file photo, a police officer walks past graffiti depicting gang members who have died during a patrol in a neighborhood controlled by the Mara Salvatrucha gang in Ilopango, El Salvador. (Salvador Melendez/AP)

Not everyone agrees that the earlier deportations are a root of the crisis. Mark Krikorian, executive director of the Center for Immigration Studies in Washington, said that while deporting gang members from the United States may have contributed to the growth of gangs in Central America, the real problem was the U.S. government’s earlier failure to enforce the law against illegal immigrants, especially criminals, in the first place.

“Our immigration policies were enforced belatedly, after we allowed these communities of illegal immigrants to grow and cause problems,” Krikorian said this week. “The deportations probably did play a role, but if the gangs had found it useful to branch out through Central America, they would have done it anyway.”

After the mass deportations of gang members, which started in the mid-1990s, Honduras, Guatemala and El Salvador received tens of thousands of jobless, alienated young men who brought new sophistication and brutality to local gangs.

From then on, the spread of gang power was abetted by several factors, experts say. One was the push of drug-trafficking routes into Central America, which brought more money and weapons to the region and spurred a rise in official corruption.

“Our deportations at the time did not cause the gang problem, but they acted as a catalyst,” said Alfonso Valdez, a gang expert at the University of California at ­Irvine and a former government ­anti-gang agent. “People were poor, and the social conditions were ripe. It was like putting a virus in a culture dish.”

In the 2000s, other factors strengthened the hold of gangs. Government instability, especially the 2009 coup in Honduras, gave them more operating room. Overcrowded prisons, especially in El Salvador, became gang command posts. Homicide rates soared, and victims became younger. According to the U.N. Office on Drugs and Crime, the homicide rate doubled in Honduras from 2006 to 2011. In the first half of this year, more than 500 Hondurans younger than 18 died in gang violence.

Central American officials, seeking to combat the wave of terror, tried a variety of methods that sometimes made things worse. In the early 2000s, Honduras militarized its national law enforcement system in a controversial mano dura, or get-tough, policy. Police and army raids threw thousands of young men into prisons for years with few legal rights. The tactic boomeranged, terrifying communities and opening the way for police corruption and abuse. Lately, a new effort at peace talks with imprisoned gang leaders is being attempted.

Sudden surge in unaccompanied children at border

“These laws had the opposite effect of what was intended,” said Adriana Beltran, who studies gang issues at the nonprofit Washington Office on Latin America. “People were swept into prisons, which became universities of crime and extortion.”

In El Salvador, an early get-tough effort also failed, so in 2012 a new government replaced it with an effort to facilitate gang truces and create “peace zones,” where gang members could receive job training and benefits if they renounced crime. This strategy dramatically reduced the homicide rate but did not make a significant dent in other gang activity. Now, Salvadoran officials are focusing on smaller communities in which gangs intimidate and extort even the poorest people — from bus drivers to shop owners — for protection payments.

“For 10 years we tried the mano dura approach, and it was a disaster,” said Rubén Zamora, the outgoing Salvadoran ambassador to Washington. “With 20,000 police and 60,000 mareros, how could we compete?” He said the new policies are more modest but have shown more promise, because they are working closely with communities. “The gang problem is local, so we’re going after it locally. It’s starting to work,” he said.

The United States, although sometimes criticized for washing its hands of Central America in recent years, has supported a number of anti-gang initiatives there in the past decade, largely in connection with efforts to combat drug trafficking. It has also continued to deport thousands of “criminal aliens” or illegal immigrants who have committed crimes inside the United States to Central America and Mexico each year.

But the pernicious sway of major gangs such as MS-13 and 18th Street has continued to reach into the United States. In 2012, the government declared MS-13 to be a “transnational criminal organization” whose activities “directly threaten” U.S. citizens and whose assets can be seized by the government. In their home countries, where lawlessness and violence are legacies of civil conflict, those two gangs alone have up to 85,000 members.

“Millions and millions of dollars have been put into security issues in the Golden Triangle, and we still have a region that is one of the most violent in the world,” said José Miguel Cruz, a political scientist from El Salvador at Florida International University. “Something has gone very wrong.”

The main reason for the continued attraction of gang life, experts say, is the lack of legitimate avenues to success for poor young men. Nearly one-third of the people of Honduras are between 15 and 24 years old; many do not attend school, have no job skills and come from scattered or dysfunctional families, thus providing what the Congressional Research Service report called a “ready pool of gang recruits.”

Those who try to leave gangs face death threats from their leaders and rejection from society.

At Casa Alianza, which helps young addicts, street children, deportees and former gang members, Ruelas said many boys are recruited by gangs thinking mistakenly that they will offer a form of protection. “First they act as lookouts, then they are assigned small crimes, and then they are forced to extort victims or be killed,” he said. “They are very vulnerable, and they can’t get out.”

While Central American governments are giving more formal attention to gang-prevention and intervention strategies, the CRS report said most such efforts have been “small-scale, ad hoc and underfunded.” Smaller scale projects run by churches and local communities have had more success, it said.

In recent weeks, the crush of Central American children on the Mexico-Texas border has triggered angry calls in Congress and in some affected communities for more and faster deportations. Critics fear the United States will be overwhelmed by a new tide of young illegal immigrants who burden schools and services, and some have called for a repeal of the 2008 law that granted temporary shelter to children from any country except Canada and Mexico who reach U.S. shores illegally.

Other Americans have expressed concern for the fate of these children if they are deported to dangerous conditions, especially without a chance to get legal help as they face their hearings.

Heidi Altman, legal director at the nonprofit Capital Area Immigrant Rights Coalition in Washington, said that she and her colleagues have represented many Central American children who arrived from border detention since 2012 and that often they had suffered unimaginable violence at home or during their journeys to the United States.

“Many of them are fleeing several levels of violence, but they are too traumatized to talk about it at first,” Altman said. If they are forced to appear in immigration court too soon and cannot fully explain what they have been through, she added, “they may end up being sent back to face “abuse, rape and horrible persecution from gangs.”

Experts such as Valdez and Ruelas said such dire assessments may not be far-fetched. Valdez noted that the largest number of unaccompanied minors reaching the U.S. border come from the area of San Pedro Sula, a city on the northern coast of Honduras that is one of the most gang-infested cities in the Americas.

“It makes no sense for us to send back kids to the most violent city in the hemisphere,” Valdez said.