Mexican President Enrique Peña Nieto would not pay for the border wall proposed by Donald Trump, he communicated through a spokesperson on Wednesday. That’s right -- Trump’s political megaphone has gotten so big that he’s earned at least half-hearted attention from world leaders on his main foreign policy alchemy. A year ago, some might not have thought it possible, but here we are . Mr. Trump has ushered his border fence proposal from the gold-plated walls of Trump Tower where he made his presidential announcement to the halls of the first Republican debate where last week he took center stage as the leader in national polls of GOP voters. It’s still a long shot from the White House -- there’s a Socialist leading polls in New Hampshire -- but again, here we are.

Eduardo Sanchez, the Peña Nieto spokesman, said in the telephone interview with Bloomberg that the administration didn’t take any of Trump’s campaign proposals seriously, but he did get on the phone long enough that it thought the proposal was rubbish. Sanchez also addressed the GOP candidate’s claim that Mexico would acquiesce to a demand to pay for a wall to keep its own citizens from leaving the country.  

"Of course it's false," Sanchez told Bloomberg. "It reflects an enormous ignorance for what Mexico represents, and also the irresponsibility of the candidate who's saying it."

Donald Trump clarified earlier this week what he meant in the Republican debate when he said that he’d “make” Mexico pay for a border wall. In an interview with Sean Hannity on Fox News aired from the now famous elevators of Trump Tower, he said that Mexico would probably just give “probably just give us the money.” As the Peña Nieto spokesperson clarified yesterday, that’s never going to happen. But Trump also suggested a second point of leverage: imposing trade tariffs, import taxes that could be used to fund a wall’s construction.

Complicating Trump’s border wall pitch -- and most of his policy proposals -- is the fact that candidate has refused to release details and facts; frameworks of how they would be executed. On it’s face, the tariff-funded border wall is not viable. The cost of a border wall is much higher than the total annual value of Mexican exports, let alone the highest possible revenues that could be raised off of an import tax. In 2013, when the construction of a border wall was proposed as a part of comprehensive immigration reform, Congress set aside 1.5 billion dollars for its construction. Trump has said that he could do it for “much cheaper.” Meanwhile, entire value of Mexican imports to the U.S. is only worth around $250-300 billion each year.

Even if Trump found a magic solution to build such a wall for half of the estimated cost, he would still have to tax Mexican exports 25 percent for 10 years straight years to pay for such a wall. Such a move would certainly drive down exports after the first few months. Worse yet, it would likely inspire Mexican tariffs on American goods, worth around $200-250 billion each years, a tax attrition that when all is said and done, might not raise one net dime. Until Trump’s campaign attempts some fact-support explanation of the plan, it’s hard to take it seriously.