Before the poem says anything, its title has already declared war. "Internecine" is the word we reach for when a conflict destroys both sides, usually a feud inside one group, such as rival factions or quarrelling relatives. Dave Bonta then gives us no group at all, only a single figure, and about twenty words that ask what it would mean for the feud to be fought entirely within one person.
The grammar is the first strange thing. Each of the three couplets opens with "who," and none of them completes a sentence. There is no main verb, no "he," no name. The poem is built from relative clauses hanging off a subject we never get, much as a proverb or a warning begins "woe to him who…". Because the person is only described, never introduced, he reads like a list of charges against someone who hasn't been identified. The reader is left to fill the gap, and may not like what fits it.
The first couplet sets appearance against damage: "who seems safe / who broke in pieces." The verb "seems" undermines the safety before the next line arrives. The tenses matter too. Safety is a present impression, while the breaking is already over. The ruin came first, and the calm surface came after. "Broke" is also intransitive, so it doesn't say who did the breaking. Did he shatter something, or did he shatter? In a poem about a person divided against himself, the missing agent makes sense, since the one doing the damage and the one damaged may be the same.
The second couplet is the knottiest: "who is aught but an argument / against himself." "Argument" works in two senses. It is a quarrel, and it is also a case put forward in reasoning, so he is both the dispute and the evidence offered against his own side. The line break helps, leaving "an argument" alone for a beat before "against himself" turns it inward. "Aught" is the only archaic word in an otherwise plain poem, and it makes the sentence wobble. Read strictly, "aught but" means "anything except," so the line would say he is anything other than an argument against himself, the opposite of what the context suggests. Most readers will hear "naught but" instead. Whether the slip is deliberate or not, a phrase that quietly contradicts itself suits a poem about self-contradiction.
The last couplet turns on a word that often pairs with others: "who will not exchange." We exchange words, or blows. The line break sets up that expectation, and then the object arrives as "his own head." The man will not trade blows, but he also will not trade heads. The head is where the argument takes place, and it is also what a violent quarrel puts at risk. His refusal could be stubbornness, loyalty, or imprisonment, since he can't or won't be anyone else. The poem leaves open which, and "own," the heaviest word in the final line, makes the conflict private property. The poem ends on the blunt monosyllable "head," with no consoling turn.
The sound is spare. There is no rhyme and no regular metre, only short lines of two to six syllables. Still, the sounds are not idle. The hiss of "seems safe," "pieces," and "himself" gives the opening a whispering, brittle quality, and "broke" and "pieces" snap with hard consonants. "Argument" and "against" both begin with *a* and carry a hard *g*, so the two opposing sides sit in the same word-family, as if the quarrel were already inside the vocabulary.
What makes the poem worth reading is how much it does with so little. It takes a word from the language of feuds and factions and shrinks it to the size of one skull. It lets the grammar do the work, with three unfinished sentences standing in for a mind that can't finish itself. It also makes a quiet point about appearances: the figure who "seems safe" is exactly the one the poem is worried about. Because he is never named, he could be a stranger, a friend, or the reader, and the poem doesn't say which. Even if you read it in thirty seconds, it is hard to put down.