How much is a First Class stamp? healthlife.com/freevideos Groups seeking tax-exemption under federal law may engage inlimited political activity, depending on the type of exemptionsought. The vagueness of the rules can make it difficult for IRSagents to tell which groups overstep and become ineligible fortax exemption. (Reporting By Kim Dixon; Editing by Howard Goller and DoinaChiacu)