When congressional committees engage in oversight of the administrative bureaucracy, or when Members of Congress intervene in agency proceedings on behalf of private constituents or other private entities with interests affecting the Members’s constituency, such interventions involve varying degrees of intrusion into agency decisionmaking processes. This report will briefly examine the currently applicable legal and ethical considerations and standards that mark the limits of such intercessions. The report initially reviews the judicial development and application of standards for determining whether congressional pressure or influence will be deemed to have tainted an agency proceeding. It concludes that the courts, in balancing Congress’s performance of its constitutional and statutory obligations to oversee the actions of agency officials against the rights of parties before agencies, have shown a decided predilection for protecting the congressional prerogatives. Thus where informal rulemaking or other forms of informal decisionmaking are involved, the courts will look to the nature and impact of the political pressure on the agency decisionmaker and will intervene only where that pressure has had the actual effect of forcing the consideration of factors Congress did not intend to make relevant. Where agency adjudication is involved a stricter standard is applied and the finding of an appearance of impropriety can be sufficient to taint the proceeding. But even here the courts have required that the pressure or influence be directed at the ultimate decisionmaker with respect to the merits of the proceeding and that it does not involve legitimate oversight and investigative functions, before they will intervene. The report next examines the conduct of Members of Congress and their staffs intervening in administrative matters from the perspective of ethics and conflict of interest rules, statutes and guidelines bearing upon a Member’s and staffer’s official duties. It notes that since congressional intervention and expressions of interest in administrative matters from a Member’s office are recognized as legitimate, official representational and oversight functions and duties of Members of Congress, the primary focus of the ethical and statutory conduct restraints is limited to(1) any improper enrichment or financial benefit accruing to the Member in return for, or because of, his or her official actions and influences, including the receipt of gifts or payments, or existing financial interests in, or relating to the matter under consideration; and (2) any overt coercion or threats of reprisals, or promises of favoritism or reward to administrators from the Member’s office which could indicate an arguable abuse of a Member’s official representational or oversight role. Additionally, ethical guidelines in Congress incorporate an “appearance” standard for Members which would counsel a Member to adopt office procedures and systems which would prevent an appearance of a “linkage” between interventions and the receipt of things of value, particularly legitimate campaign contributions, and which would assure that decisions to intervene are based on the merits of a particular matter.