The Arizona-Mexico border fence near Naco, Arizona, March 29, 2013.
Samantha Sais/Reuters

Trump moves forward with a dubious plan for a border wall

— Updated
Donald Trump didn't offer much in the way of specific policy proposals during his campaign, but he seemed awfully fond of one idea in particular. The Republican routinely told audiences that he'd build a giant wall along the southern U.S. border -- which spans nearly 2,000 miles -- and it wouldn't cost American taxpayers a dime because Trump would get Mexico to pay for the whole thing.

He largely avoided going into any details as to how he'd achieve any of this, but Trump knew his rabid followers loved the idea, so he made it a central point of his candidacy. Today, as the Washington Post reported, the new president moved forward with his plan.

President Trump signed a pair of executive actions Wednesday to begin ramping up immigration enforcement, including a new border wall with Mexico, vowing that construction on his chief campaign pledge would begin in months. [...]

The construction of a wall along the southern U.S. border was Trump's chief campaign promise as he blamed illegal immigration for constricting the U.S. job market for Americans and adding to national security concerns. But it remained unclear how Trump's directive would accelerate construction of the wall, the funds for which would have to be appropriated by Congress, or pay for the added enforcement tools and border control agents.

At the risk of spoiling the White House's fun, the details are pretty important in a case like this. A wall such as the one Candidate Trump promised would cost tens of billions of dollars -- and the administration doesn't keep money like that sitting between the couch cushions.

With that in mind, the point of today's announcement wasn't entirely clear. Trump didn't launch the wall project today and he didn't formally request the money for the wall from Congress. By all appearances, today was about little more than initiating a process.

Or put another way, the president now plans to have a plan to someday have a wall that Mexico will someday pay for.

Some skepticism is still in order. Before his inauguration, Trump insisted in a tweet that he'll get Mexico to finance the project "later," which was just vague enough to be useless. Soon after, John Kelly, Trump's new Secretary of Homeland Security, seemed less than excited about the idea, telling senators that "a physical barrier in and of itself will not do the job."

In a Fox News poll released last week, just 6% of self-identified Republicans said building a wall and immigration in general should be a top priority for the new White House.

So why bother with this? The Washington Post's Greg Sargent had a good piece on this recently, explaining that the real immigration battles of Trump's term will likely have very little to do with a wall that's unlikely to be built.

...I'd wager that Trump is thumping his chest about this right now to buy himself goodwill with his base -- and with the immigration hard-liners -- in case he ends up selling out on any of the more consequential tough-on-immigration promises he made during the campaign. [...]

Trump has to decide how, or whether, he's really going to ramp up the deportations in any kind of significant way, as he promised to do. He has said he will start with the criminals first, which, at bottom, is an admission of the real problem here: The executive has to prioritize who to remove, due to funding and other constraints, and that means he has little choice but to proceed as Obama did -- that is, prioritize the removal of the most serious offenders. Trump may try to ramp up the deportations beyond that, but this might create all sorts of other problems that he may balk at. And this, too, would lead to a lot of media stories about families of longtime residents being ruptured in all sorts of cruel ways. That is where the real battles will be fought. The wall, while important in many ways, is a sideshow to those things.

All of this should come into focus fairly quickly. During the campaign, Trump said a "big, beautiful wall" along the Mexican border "will go up so fast your head will spin."

Correction: To clarify a point I've now removed, Trump wants the Department of Homeland Security to use existing funds to start building his wall, but since DHS doesn't have an extra $20 billion, wall proponents shouldn't get too excited just yet.