This line, late in “A Modest Proposal,” heightens the piece’s overall satirical effect. Up to this point, the satire has derived chiefly from the absurd proposals. When the reader encounters the "unless," the reader might think that the writer is about to acknowledge that, after all, the idea of eating babies is morally wrong. Swift subverts this expectation by continuing the satire, naming the unexpected objection of mere population depletion. Although the Irish are the enemy and it is better to have few of them, at least they help develop the economy and the countryside. With this added irony, Swift is further heightening the satire, suggesting that the writer does not even conceive that the idea of killing and eating Irish one-year-olds could be morally wrong.