Rational manipulation is constituted by the following conditions: (i) A aims to persuade B of thesis X; (ii) A holds X to be true and rationally justifiable; (iii) A knows of the existence of evidence, argument or information Y. While Y is not itself misinformation (Y is factually correct), A suspects B might take Y as important evidence for not-X; (iv) A deliberately chooses not to mention Y to B, out of a concern that it could mislead B into believing not-X; and, (v) B has no compelling reason to expect A will avoid mentioning Y in this way. A’s behavior is rational insofar as A aims to use reasons to persuade B to believe a thesis that A holds as true and justified. Yet it is manipulation because A deliberately avoids furnishing B with information that B might regard as relevant, to ensure B arrives at the correct belief. I argue that we have good reason to think that A’s action will be wrongly manipulative because it disrespects B’s consent, epistemic autonomy, and personal autonomy. That said, context is critical, and there are many times evidence is intentionally occluded that are not rational manipulation. Even so, ethical arguers should beware of ambiguous contexts, such as when there are conflicting expectations about argumentation roles and goals.