Presenting a choice as binary — A or B — when other options exist. By collapsing the possibility space, one option can seem inevitable once the other is rejected.
"Either you support this military operation, or you support the terrorists." This eliminates the vast middle ground: people who oppose terrorism and also oppose the specific military response. False dichotomies are common in political messaging because they prevent nuanced positions from forming and force audiences into pre-defined camps.
Binary choices are cognitively efficient. "Pick one of two" is simpler than "evaluate a spectrum of options." Once a false dichotomy is accepted, the entire debate moves onto the terms the dichotomy sets — which almost always favor one side.
"Either X or Y" framing, "if not A then B," and "you're either with us or against us" logic. Ask: "What options are being excluded by framing this as a choice between only two things?"