Plagiarism:

[rowens]

I don't think anyone should use someone else's words for the sake of passing them off as their own. And I consider a poem where someone uses someone else's words to be a minor expression, at least if that's what gives the whole poem its life. I think if the lines are used, not only in another context, but out of the original context, or the poem is trying to express a theme of confused identity, or kind a of criticism, or a theme of weakness, or some theme of merging, or a question of persona, and individual authenticity itself, a feel of plagiarism is what is wanted. Acknowledging the other poet in a footnote would lessen that. So if it's not a blatant enough thing, there should be some hints that these words are someone else's, I don't think they should blend in easily with the rest of the poem. As for the immorality of plagiarism, that would factor in, within the new context, the effect would depend on the reader making that connection. If that connection's not made, or not made enough, then the context fails. Or at least part of it fails.