Delays were already rising at several key border crossings as Trump ratcheted up pressure on Democrats in Congress to toughen United States laws against illegal immigrants, threatening to hurt the U.S. economy in the name of border security.
"This would create a national recession", Saenz says. The U.S. State Department confirmed on March 30 it has stopped aid to the three countries of the so-called Northern Triangle after Trump repeatedly warned them he would do so if they fail to stem the migration.
Trump lashed out at the right-wing and corrupt US-backed governments in Central America, tweeting that they "have taken our money for years, and do Nothing".
Mexico's foreign minister, Marcelo Ebrard, also noted commercial traffic at the US-Mexico border had slowed at several crossings. Making a mockery of our security clearance process and letting those with potential problems have access to our most closely held secrets is a disaster waiting to happen.
It was a shift from Trump's threat late last week to seal the border, and quickly. One only need add the unspoken thought, "At least not yet".
He expressed similar sentiment the day before, urging Mexico to stop two large caravans of migrants traveling north from Guatemala.
Trump also left open the possibility of closing sections of the southern border instead of the entire border.
A border closure would squeeze USA corn, soybean and dairy farmers, too, if they can't ship their produce into Mexico.
This cruel policy has been implemented as U.S. migrant detention facilities are overflowing, with over 13,000 children being held in appalling conditions. This number may be expanded to 2,000, forcing the shutdown of entry lanes and a dramatic slowdown for those trying to cross the border. Trump has threatened to close the border before but not acted on the threat. But the other rough half is of trade is trade in intermediate parts. But if a shutdown blocks trade, too, it would disrupt the daily flow of $1.7 billion of goods to store shelves and factory floors.
"But he says that he's "ready to close it" if he has to and will do so if Mexico stops helping or if he fails to reach a deal with Congress to overhaul the nation's immigration laws".
"We are watching it and looking for ways to allow the freight passage, some people call it truck roads, and there are ways you can do that which would ameliorate the breakdown in supply chains", the veteran financial guru and former Ronald Reagan adviser told CNBC.
"We have seen Mexico earthquakes, coastal labour disputes at ports of entries and tsunamis".
The irrationality of this approach is breathtaking.
More than 60 percent of all Mexican winter produce consumed in the USA crosses into the country at Nogales, Arizona.
A group representing General Motors, Ford Motor and Fiat Chrysler Automobiles said in a statement that "any action that stops commerce at the border would be harmful to the USA economy, and in particular, the auto industry".
"Closing the border would cause an immediate depression in border state communities and, depending on the duration, a recession in the rest of the country", he said.