Back in August, Donald Trump first broached the idea that he would make Mexico pay for a yuge and totally awesome wall/fence along the US-Mexico Border. This was his proposal at the time:

Mexico must pay for the wall and, until they do, the United States will, among other things: impound all remittance payments derived from illegal wages; increase fees on all temporary visas issued to Mexican CEOs and diplomats (and if necessary cancel them); increase fees on all border crossing cards of which we issue about 1 million to Mexican nationals each year (a major source of visa overstays); increase fees on all NAFTA worker visas from Mexico (another major source of overstays); and increase fees at ports of entry to the United States from Mexico [Tariffs and foreign aid cuts are also options]. We will not be taken advantage of anymore.

I’m not sure the wall is such a great idea. As we know most illegal immigrants go home regularly and intend to return home permanently, a really secure southern border encourages what would be temporary illegal workers to become permanent illegal residents as they can’t be sure they can come back into the US after a visit home. But let’s concede, arguendo, that the wall is a really wonderful idea. How will we make those evil Mexicans pay for its construction and security and maintenance? Not an easy question. For instance (skip to :20 and turn your speakers down because it is NSFW)

Now Trump has given the Washington Post as close to comprehensive plan to accomplish this task as we are likely to see from Trump. You can read the actual letter here. You should. You really should.

This is the guts, such as it is, of the proposal:

I’m not going to deal with whether he could actually do this, as we’ve seen over the past eight years a determined president can do most anything he wants to do. The issue is whether this will accomplish the intended purpose.

Will shutting down remittances, via wire transfers, increase or decrease NET illegal immigration? If the guy who picks tomatoes in the San Joaquin Valley can no longer send money home what will he do? Will he actually stop coming to the US to work? Or will he save the money up and take it home in cash? Or (my favorite) will he decide that the whole migrant worker life has become too uncertain and just bring his whole family to the US for good?

Is targeting wire transfers going to work? What stops an illegal from buying a pre-paid Visa/Mastercard and mailing it home? How about debit cards on US banks? PayPal accounts? Wouldn’t this spawn an unregulated market in moving cash to Mexico?

Is an (more) economically and politically unstable Mexico on our southern border likely to result in more or less illegal immigration? Is a destabilized Mexico a desirable thing from a US national security point of view?

What is the state of US trade with Mexico? Let’s ask the US Trade Representative:

Mexico is currently our 3rd largest goods trading partner with $507 billion in total (two ways) goods trade during 2013. Goods exports totaled $226 billion; Goods imports totaled $280 billion. The U.S. goods trade deficit with Mexico was $54 billion in 2013.
…
The top export categories (2-digit HS) in 2013 were: Machinery ($38.5 billion), Electrical Machinery ($36.7 billion), Mineral Fuel and Oil ($23.0 billion), Vehicles ($21.6 billion), and Plastic ($15.3 billion).

U.S. exports of agricultural products to Mexico totaled $18.1 billion in 2013, the 3rd largest U.S. Ag export market. Leading categories include: corn ($1.8 billion), soybeans ($1.5 billion), dairy products ($1.4 billion), pork and pork products ($1.2 billion), and poultry meat (excluding eggs) ($1.2 billion).
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U.S. goods imports from Mexico totaled $280.5 billion in 2013, up 1.0% ($2.9 billion) from 2012, and up 103% from 2003. It is up 603% since 1993 (Pre-NAFTA). U.S. imports from Mexico accounted for 12.4% of overall U.S. imports in 2013.

The five largest import categories in 2013 were: Vehicles (cars, trucks and parts) ($59.6 billion), Electrical Machinery ($57.4 billion), Machinery ($42.6 billion), Mineral Fuel and Oil (crude) ($34.8 billion), and Optic and Medical Instruments ($10.7 billion).

Notice the Mexican exports to the US are not mostly taco trucks and sombreros. Those vehicles that lead the export list are American/European brands that are assembled in Mexico from parts manufactured in the United States and Canada. Slapping import duties would not only be really stupid, not that that is a substantial deterrent in this case, as US auto workers would be hurt just as much as Mexican workers, but it would also be in violation of NAFTA… which is actually has the force of law. Again, this is only a minor impediment to someone as truly awesome as Trump.

We can agree on disagree on whether a wall is a great idea. But we should all be able to agree that the idea that we can coerce Mexico into funding its construction, much less its maintenance and the massive expansion of the Border Patrol it would entail, is simply lunacy. And the notion that we can take these punitive actions without US workers and businesses suffering in a major way is dishonest lunacy.