The title does a lot of work. "Tarnation" is an old, mild curse, a softened "damnation". Dave Bonta splits it into "Tar nation", and the two halves come loose. Tar is black, sticky and hard to scrub off, and nation is a collective we are born into. The poem never says which nation or which argument it means. That openness lets the nine lines read as a comment on any divided public quarrel, and on the private habits that feed it.
The first stanza states its idea like a proverb: "in the middle of an argument / kindness is fatal / to keeping the enemy an enemy." There is no pronoun and no punctuation, so the claim arrives as a plain law of human behaviour. "Fatal" is the word to watch. Kindness is usually the gentle option, but here it is treated like a poison. The thing it kills is the enmity itself. The repetition in "the enemy an enemy" makes being an enemy sound like a job that has to be kept up. Someone has to maintain the role, and one kind gesture could end it.
The second stanza turns personal, and the tone changes with it. "My friends think / I am an old hen / dancing without a head." The line break leaves "my friends think" hanging for a moment, and there is an irony in it. The people who think are accusing the speaker of having no head. The image comes from the familiar picture of a headless chicken running in panic, but Bonta says "dancing". That word is lighter and almost festive, which makes the flailing stranger and sadder. "Old hen" adds a faintly mocking, fussy, domestic note. The stanza follows straight from the first, so the poem seems to suggest that the speaker has been kind in the middle of an argument and that his friends now read this as lost reason. Treat that link as an inference, but the placement of the stanzas invites it.
The last stanza widens from "I" to "us". "Between hope and fear / what will become of us / running on other men's ruin." The first line is the only place in the poem where two forces are set in balance, and it sits in the middle of the stanza, as if the whole group were stuck on a tightrope. The question has no question mark, so it hangs unanswered. Then comes the final image. "Running" picks up the hen's frantic motion, but it also sounds like an engine. If we run "on" something, it is fuel. Given the tar in the title, the imagery suggests oil or asphalt, though the poem never says so. The fuel in question is "other men's ruin." The sound of "running" and "ruin" links them, as if one grows out of the other. The comfort and momentum of one side depend on someone else's loss.
Formally, the poem is three unrhymed tercets in free verse with no end stops. The lines are short and conversational, and the opening line is among the longest, so the stanzas thin out as they go. Every stanza ends without a full stop. The poem begins "in the middle" and stops in the middle, which suits a subject that has no clear start or end. The plain vocabulary also matters. There are no ornate metaphors, only a hen, an enemy and a verb of motion. The quiet voice sets off the harshness of the claims.
The poem is significant because it compresses a whole psychology of conflict into very little space. It does not tell us who is right in the argument. It shows what arguing does to the people in it. Enemies can be useful, because they give friends something to agree about. Gentleness can then look like betrayal or foolishness. The speaker is not above this, since "us" includes him. The poem also gives no answer. It ends on the image of a machine, or a headless bird, still moving on borrowed ruin, and leaves the reader to decide whether to keep running.