The practice of stonewalling has been omnipresent in American public life since at least the days of Thomas Jonathan Jackson during the Civil War. However, in actual reality there are a variety of expressions and styles and classifications, of which I wish to elucidate 2.
First is the dressed stone wall in which stones are quarried out of the bedrock and shaped so that they can be laid in regular courses. The advantage of dressed blocks is that the resulting wall is more solid. A solid wall repells more types of infiltration more successfully over more time which makes such a wall more valuable if (as one would usually suppose) the intent of the builder is to exclude outside influences. The compensating cost is the need to quarry and dress the stone.
Second is the field stone wall in which stones are assembled in the state in which they occur in nature: rough and rounded. Such a wall is considerably more porous than the dressed block wall; it can only be made solid with the liberal use of mortar (which is itself porous and weak in comparison to the dressed blocks above). The raw material for the field stone wall is frequently available at little or no cost, especially in glaciated areas. The deficiency of a field stone wall is that it may fail to exclude water, snakes, rodents, and other outside influences. These not only may pass through the barrier, limiting its effectiveness, in the end they actively destabilize the wall's structural integrity.
One should not assume that in actual reality the field stone wall is chosen only when one is too impoverished or too cheap to pay for the quality of dressed stones. In some cases, the qualities of porosity and impermanance may be precisely the qualities desired in a stone wall.
I leave to the reader the question of whether it is ever wise to build a wall with the intent of allowing the snakes to get through. Consider this excerpt from an actual stonewalling email: "Given that this approval just happened last week, we have not posted information on our website, but we will do so. The questions that you are asking are important and quite frankly are some of the reasons why this alternative is being pursued. ... I anticipate that there will be meetings within the community on this idea." [Greg Maass, 4/13/2009] There is no hint here of actually providing any information. I would paraphrase it thus: (1) we haven't provided anything to you, although we may later, and (2) everything you've said is something.
That's a stone wall. But it is field stone. There are tons of holes in this message. The author didn't invest the time, effort, or skill required to create an impermeable barrier. Why not?
In the actual reality of public agencies in the United States, a truly impenetrable stone wall would be subjected to a frontal assault in the press and likely the courts, in addition to resistance by an aroused civil population and sapper attacks from all sides. The wall would almost certainly fall to the attackers and likely take its defenders with it.
The field stone wall, unmortared and only a few courses high, is less likely to incite such a dramatic defensive response. Stonewallers seem often to underestimate the disgust their efforts engender but they are correct in observing that a neighborly stone fence is less of an offense in most citizens' eyes than a tall battlement. The less threatening wall may last longer and be more protective than would an obviously better wall which attracts a stronger attack.
That's the actual reality of stonewalling today.