The president, going clear back to his election campaign, has been adamant about the need for a wall — a physical barrier as impregnable as humanly possible — to protect our southern border from the constant inflow of illegal aliens, narcotics, and contraband, while at the same time impeding the southward flow of laundered money and weapons to the powerful cartels operating throughout Mexico.

Among the pillars of the White House's recently promulgated immigration framework, constituting the underpinnings necessary for immigration reform before the president will commit to signing a bill, was the proposal for a $25 billion trust fund for border security enforcement, including most specifically the wall.

Almost all Democrats, and some number of Republicans, have placed themselves in opposition to the border wall, sometimes going so far as to ridicule it. One Mexican congressman attempted to do the same by scaling an existing piece of fence, proving only, in my view, that much of what is there is inadequate, despite which it has been singularly effective.

There have been other attempts to obstruct construction of a wall, including threats to boycott companies that bid on the wall contract, and buying and then re-parceling out small pieces of border property with the idea of forcing the federal government into protracted and expensive litigation before a single barrier panel or bollard can be erected.

Among the chatter, there has been a great deal of talk about a wall being archaic, that a better way toward border security is through smart use of technologies.

This kind of talk resonates with me, but not in a particularly good way. In the decades I worked as an immigration agent with the now defunct INS (Immigration and Naturalization Service), we too were often told to "work smarter, not harder". The other verbal shoe that usually dropped right afterward was the observation that in doing so, we would be able to "do more with less".

The wags among us within the INS Investigations Division often quipped that by the time we got done doing more with less, we would be able to do everything with nothing.

They weren't too far off the mark, because those two aphorisms manifested themselves in the worst of ways. When I began government service in the mid-1970s, there were around 2,000 investigators nationwide; by the time I retired, we had been allowed to shrink to a low of about 850.

Even 2,000 agents was a totally inadequate number, but at the point of low ebb, as I have pointed out before, there were more Capitol Police officers guarding the 535 members of Congress in the few square miles of the Capitol grounds than there were agents to enforce immigration laws in interior of the 3.8 million square miles of the United States.

I am not simply reminiscing here. There are several points contained in my ruminations that relate directly to "the wall".

First, a wall exists independent of the waxing and waning of the available cadre of border enforcement agents, something that has always been subject to the vagaries of the legislative and executive branches. Congress may or may not appropriate the money to staff officers and agents up to the required levels; and if they do, a recalcitrant or anti-enforcement president such as Barack Obama may choose to not take advantage of the money and simply let the funds sit idle until year's end when they revert back to the Treasury.

Second, and it is a corollary to the above, it is a mistake to think that "smart" technologies somehow supplant the need for a robust officer corps. To the contrary, they absolutely demand it. Every kind of technological advancement, whether it is drones, military-grade sensors, forward-looking infrared radar (FLIR), tower-mounted high powered cameras, or something else, requires a sufficient number of human beings — of trained agents — to respond to intrusion alerts. Law enforcement always has been a human-resource-intensive occupation, and technological wonders won't change that equation, at least, not until we see walking, talking androids capable of apprehending aliens, putting the cuffs on them, advising them of their rights, and transporting and processing them.

Third, and this is critical, all of the smart technologies that have been mentioned in the context of border technology are reactive in nature. They alert agents to respond after an alien has crossed into the United States, and thus has been imbued with constitutional rights to hearings, to make claims, seek various forms of relief, and to stall in each and every way possible his or her removal, no matter how immediate in time or place he was arrested relative to his illegal entry.

The harsh reality is that due process in the immigration context is breaking down. The immigration courts are thoroughly backlogged into the several hundreds of thousands. This, in turn, forces inappropriate or premature release of aliens from detention as the available space is filled. And that, in turn, leads to the kind of situation we have now, wherein there are more than 900,000 (yes, you read that right, nearly a million) aliens loose in the United States who have either absconded from their hearings or failed to report for removal as required.

With an intelligently (dare I say "smartly") built border barrier, aliens don't make it into the United States. They have no due process claims; they don't need to be arrested, or detained, or put into an interminable court queue. They aren't here and therefore can't abscond. Finally, because they never made it in, they don't need to be repatriated at tremendous taxpayer expense (if and when that day ever arrives, years after the fact).

When all is said and done, that salient fact, ladies and gentlemen, is the implacable logic behind erecting a wall.