I find this poem to be easily read on a variety of levels, first, of course, being a literal level with two neighbors mending the wall between the two. "Good fences make good neighbors," (line 27) according to the man's father. The quote is a reference to the man's inability to be an individual, and his inability to move past his father's beliefs and thoughts, and gain his own. The neighbor is the one with the desire to maintain the wall between their properties; however, it doesn't appear that the narrator puts up much of an argument. I believe, the narrator's main and most important point is "Before I built a wall I'd ask to know/What I was walling in or walling out,/And to whom I was like to give offense." (lines 32-34). The narrator makes a great emphasis as to the actual point of the wall; however, the question is, is he speaking of a physical wall or a wall within us?
I believe the poem to be most effective when referring to putting up an inner wall, a defense against anything or anyone getting in (into your heart, into your trust, etc.).
The neighbor is called "an old-stone savage..." (line 40). By the end of the poem, it has moved into a much darker connotation. Frost brings in words like "elves," "old-stone," "savage," "darkness," etc, which gives the reader a more down trodden feeling towards the neighbor and the wall. I believe that it makes the neighbor easier to identify with and possibly even sympathize with. The neighbor can even be seen as becoming menacing even though he has been the one to protect his boundaries by continuing to mend the wall.
However, after close analysis of the poem, the reader determines that it is...