A US Border Patrol agent detains migrants at the border in El Paso, Texas. Photo: Getty Images.

A US Border Patrol agent detains migrants at the border in El Paso, Texas. Photo: Getty Images.

Donald Trump’s latest border security play – which slashes the State Department’s foreign assistance to three vulnerable Central American countries at the same time as he fixates on building a wall – won’t fix illegal migration. Worse, it siphons away money from solutions that will actually improve US border security.

It has been well documented that the answer to southwest border migration is not building a wall, it’s first improving the US immigration system. The system is badly broken, ill-equipped to manage the flows of people seeking to work, live and seek refuge in the United States. Both presidents George W Bush and Barack Obama tried – and failed – to get reforming legislation over the finish line, thwarted by partisan bickering.

However, unless the underlying drivers of migration are fixed, no immigration system – and certainly no wall – will keep out the most desperate people. Despite the very real stories of the dangers of the journey from Central America to the United States – children kidnapped, raped, brutalized or disappeared en route – Central American parents are making the tough choice to put their kids, sometimes as young as 2 or 3, in the hands of a smuggler rather than face the much more certain dangers at home.

This is why foreign assistance is so critical. Starving the countries of the resources they so desperately need to address the crime, violence, and lack of opportunity in their countries is a recipe for more migration, not less. Building relationships with – not bullying – the countries in the region is the only way to solve the problem.

In 2014, the number one factor that slowed the wave of Central Americans coming to the US border was the engagement of the Mexicans in managing their own border. Once Mexico enhanced its own border management – often with the instruction of US border patrol and immigration agents paid for by the State Department – the total number of migrants dropped by over 14,000 in just one month in the Rio Grande Valley alone. And it’s not just Mexico – Panama, Costa Rica and other countries in the region are valuable partners in managing today’s migration.

This also means the US must continue to invest in the region. The children and families fleeing Central America have many reasons for coming to the US. Many are fleeing horrendous gang violence, targeted themselves or ducking bullets in their neighbourhoods. School is minimal, jobs are scarce, and their governments unable to help. Ignoring the reasons why people leave in the first place is shortsighted, undermining long-term border security.

Investing in the region does come at a price. But the cost for foreign assistance in the region is a fraction of the billions of dollars it costs to shelter, place and manage the immigration cases of these children and families once they arrive in the United States.

And it is not a short-term solution. The lessons learned from US investment in Colombia, for example, demonstrate that success requires time. There, US foreign assistance over a period of 15 years transformed the country from an extremely violent fragile state to a strategic ally and economic partner.

Success also requires political will and accountability from the receiving countries. Congress should continue to require proof that Central American governments are meaningful partners in confronting the crime, violence and corruption that cause people to flee.

The maths are simple. Instead of wasting tens of billions of dollars to build a wall and slashing the small proportion of dollars to the Northern Triangle countries, the United States should be building a real partnership with Mexico. It should be investing in reversing the violence in Central America. And it should rebuild its broken immigration system. These efforts would be a much smarter investment in real US border security.