The ethics laws traditionally have afforded criminal defense attorneys greater latitude than other lawyers in their use of aggressive strategies on behalf of their clients. Federal judges nonetheless attempt to regulate zealous, or what is perceived as overzealous, advocacy by criminal defense lawyers. They do so by using the “acceptance of responsibility” provision of the United States Sentencing Guidelines to impose harsher sentences on criminal defendants whose attorneys engage in aggressive forms of representation, such as making factually or legally dubious arguments, seeking tactical delays, or misleading the court. Judges justify these higher sentences by equating a zealous defense with remorselessness. This interpretation of the sentencing laws chills zealous advocacy in a fashion that has escaped review by most courts and scholars. This Article explores this method of regulation and its troublesome implications for criminal defendants and the attorneys who represent them.