Yesterday, the president of the United States, Donald Trump, again threatened that if his Mexican counterpart does not stop the flow of Central American immigrants arriving at the border with the intention of traveling to the U.S., he will fully or partially close the border that separates his country from Mexico. The new barrage of bravado is directed against Mexico and the Democratic Party, which he blames for his country’s weak immigration legislation. This threat this week differs from preceding threats, as for the first time he has announced a deadline for the drastic measure, which he hopes will transform the xenophobia of his citizens into a permanent campaign.

Despite the flippancy with which the business mogul talks of closing the 3,000-kilometer (1,864 miles) border separating him from his third biggest trading partner, it is in no way a minor issue. More than 1 million people a day cross through the numerous entry points to study or work on the other side of where they reside. The metropolitan area formed by Tijuana and San Diego alone contributes to human traffic ranging from 100,000 people a day to more than 30 million a year. In addition to the movement of humans, there is also commercial traffic. It is estimated that every day, the customs office witnesses the passage of $1.4 billion worth of goods, which in economic terms makes this border the most important in the world. For U.S. territories next to the border, the eventual halt of this trade would be simply catastrophic. In the case of Texas, 463,000 jobs (and $94 billion) depend on business through the border with Mexico, and in California, this number rises to 692,000.

Naturally, the consequences of prohibiting or restricting the bilateral passage of goods and people will set off alarm bells on both sides of the border and will generate intense pressure from U.S. business organizations to ensure that the Republican leader will under no circumstances move from words to action. Not only does lobbying stand between Trump and his nefarious intimidation tactics, but also the fact that while the presidential system of governance in Washington awards ample power to the head of state, so, too, does it empower a series of legal restrictions that would impede or reverse a unilateral border closure. These range from a lack of any legal precedent for stopping American citizens from returning to their country from Mexico, to specific provisions in the North American Free Trade Agreement. It is also worth mentioning the previous history of the courts reversing his other intended actions, such as his proposed travel ban on citizens from Muslim-majority countries.

Unfortunately, it is not even necessary for Trump’s threats to come to fruition to cause damage. After a series of tweets explaining his proposals, this damage was demonstrated by the fall in price of the peso and the slowing of the Mexican stock exchange. For the material and human losses that it brings, not only to Mexico, but to his own country, as well as the proven futility of these types of measures for controlling the flow of migration, the entire American political class should appeal to the tycoon to cease his use of this political and propagandistic rhetorical device, which it is so easy to lose control of.