Journal article: Can an incumbent political party increase its chances at re-election by implementing inefficient policies that harm its constituency? This paper studies the possibility of such a phenomenon, which we label political entrenchment. We use a two-party dynamic model of redistribution with probabilistic voting. Political entrenchment by the Left occurs only if incumbency rents are sufficiently high. Low-skill citizens may vote for this party even though they rationally expect the adoption of these policies. We discuss: the possibility of entrenchment by the Right; the scope for commitment to avoid entrenchment policies; and the effect of state capacity, income inequality and party popularity on the likelihood of entrenchment. We illustrate our theory with a number of historical examples.