On April 1, President Donald Trump vowed to cut off aid to three Central American countries, due to a wave of people trying to flee violence and economic devastation and enter the United States.

But on Monday, five retired top military officers who oversaw American operations in the region said it’s a really, really bad idea.

The former four-stars were all the chiefs of US Southern Command, the military organization that orchestrates operations in Latin America and the Caribbean, and served in that post at varying points throughout the previous three administrations. One, retired Navy Adm. James Stavridis, was once rumored to be in consideration as Trump’s secretary of state.

According to them, Trump’s decision will not stop the flow of migrants trudging northward.

On the contrary, it’ll only make things worse.

“Improving conditions in Honduras, Guatemala, and El Salvador is a critical way to address the root causes of migration and prevent the humanitarian crisis at our border,” the retired soldiers, sailors, and Marines wrote on Monday. “Cutting aid to the region will only increase the drivers and will be even more costly to deal with on our border.”

Five former SOUTHCOM commanders have released a statement condemning the Trump administration's decision to cut aid to Northern Triangle countries... (h/t @cjf39) pic.twitter.com/kvXfg2WqFf — Elizabeth McLaughlin (@Elizabeth_McLau) April 8, 2019

Lest you believe the view of these retired troops is outdated, some top people in the Trump administration share it.

“We also need to invest in Central America,” Kevin McAleenan, the commissioner of US Customs and Border Protection whom Trump just named as the acting homeland security secretary, told ABC News in December. “[B]oth on security and the economic front in Central America, we need to foster that and help improve the opportunities to stay at home.”

The former military officials have a point

It’s very unlikely that Trump will change his mind about sending aid to the “Northern Triangle,” as the three countries are collectively known, but he would do well to listen to the former officers.

As the Washington Post noted on April 1, US assistance has helped curb migration flows from El Salvador. More than 72,000 Salvadorans were detained at the US border in 2016; in 2018, that number hovered around 32,000.

“The decision to cut funding contradicts the results of what we have accomplished together,” Raúl López, El Salvador’s vice minister of justice, told the Post.

But Trump has preferred a more military-centric approach to safeguarding the border, including sending thousands of US troops to the boundary with Mexico to quell what he considers to be a national emergency.

The former military chiefs, however, say that’s wrongheaded. “We have seen firsthand that the challenges in the region cannot be solved by the military alone,” they wrote, “but require strengthening investments in development and diplomacy.”

Trump usually brags about the toughness of America’s military brass, but it’s unlikely he’ll champion the former officers openly telling him he’s failing on one of his core initiatives.