37 CFR §11.301
Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
A practitioner shall not bring or defend a proceeding, or assert or controvert an issue therein, unless there is a basis in law and fact for doing so that is not frivolous, which includes a good-faith argument for an extension, modification or reversal of existing law.