Three weeks ago I traveled to Dilley, Texas, to assist the hundreds of migrant mothers and young children detained at the South Texas Family Residential Center. This sprawling trailer jail was constructed in 2014 under the Obama administration to detain the growing number of families crossing the southern border and requesting asylum. The possibility of being imprisoned by the U.S. government did not deter these mothers from El Salvador, Honduras and Guatemala, who are fleeing unrelenting violence from gangs, narcotics traffickers and their own abusive spouses.

I was volunteering with the Dilley Pro Bono Project. I met with asylum-seeking mothers to help prepare them for a “credible fear interview” with an asylum officer, which would determine if they could stay in the U.S. and apply for protection. We volunteers tried to explain the complexities of asylum law to these mothers in minutes — what suffering mattered and what didn’t, which perpetrators our laws protected against, and which ones it didn’t. All the while, their toddlers fussed, cried, sneezed, coughed and dirtied their diapers. I always brought in a pen and paper in case their kids wanted to draw. Crayons were no longer allowed according to the guard because the “kids were drawing on everything and no one seemed to care.”

After prodding these mothers with endless questions and eliciting agonizing details they never wanted to share, I was left with one thought: None of these mothers had a choice. And this is why policies of deterrence will fail every time.

Even the most vicious deterrence policy — family separation comes to mind — cannot stop genuine refugees from seeking protection. Economic migrants, conversely, may be more inclined to weigh the risks and benefits of migration. The U.S. has seen a consistent decline in unlawful border crossings since 2000, with numbers correlated to the U.S. unemployment rate and thus job availability. However, the number of families attempting to enter the U.S. and expressing a fear of return does not follow this pattern. These families will continue to flee until the violence and lawlessness forcing their journey abates.

The Trump administration’s latest deterrence effort forces asylum seekers to remain in Mexico with limited or no access to counsel while immigration judges in the U.S. adjudicate their cases. The administration claims people will be permitted to enter for their hearings. This policy is an egregious derogation of our obligations to asylum seekers under U.S. and international law. When will the U.S. stop inventing new ways to tighten the screws on the world’s most vulnerable people? Like all the others, this new deterrence policy will fail. In the meantime, these asylum-seeking families will be victimized by new perpetrators and live in squalor for months or even years.

The only way to stem the flow of people fleeing persecution is to stop the persecution. The United States must dramatically shift its attention and resources to constructive engagement in El Salvador, Honduras and Guatemala, implementing a Marshall Plan for the region. We should be partnering with Mexico — not to warehouse asylum seekers but to promote economic development, to invest in anti-corruption efforts and to bolster government protections against violence and organized crime.

This is not a far-flung fantasy. Engagement efforts are growing. But they need a groundswell of support and then time to make an impact. Until that happens, the U.S. government is legally and morally obligated to provide a fair, safe process to all asylum seekers here.

Throughout the detention center, there are signs in Spanish saying “Mothers Take Care of Your Children. They are Your Responsibility.” They struck me not just as irritating paternalism but painfully ironic. Take care of your children? These mothers fled persecution for their children, not in spite of their children. And until we address the root causes of migration, there is no deterrence policy that can stop them.

Meg Hobbins (mhobbins@grossmanyoung.com) is a senior attorney at the firm of Grossman Young & Hammond and was formerly a judicial law clerk to the Baltimore Immigration Court.