If flexible coordinative planning's advantages for a place like the Potomac Basin are recognized, and it is accepted as the most reasonable and hopeful way to approach problems there, the question arises as to what kind of agency is best suited to carry it forward and to act on it. Besides certain unique agencies like the Tennessee Valley Authority several types of institutions are available that can be oriented toward a whole interstate river basin. An _interstate compact_ is a detailed agreement between two or more States to act toward a common specific goal. It needs the approval of Congress, but the Federal government usually takes no formal part in the compact commission's activities, nor are Federal activities in the basin subject to compact commission control. A _Federal-interstate compact_, on the other hand, does have Federal participation and provides for some limitation on Federal freedom to act on basin problems without compact commission consent. Compact commissions under either of these types of agreement can have wide or quite limited powers in regard to planning, construction, management, and such things, depending on the specific agreement itself. Two kinds of Federally-directed bodies with primary emphasis on planning are in operation in various river basins. _A Title II river basin commission_, as defined in the Water Resources Planning Act of 1965, is formed by the President to carry out comprehensive basin planning, with a Federal chairman and members from Federal agencies, Basin States, and approved interstate or international agencies with jurisdiction in the Basin. A _Basin inter-agency committee_ is created by agreement among Federal agencies for an assigned mission, usually the coordination of Federal and State planning through the exchange of information about programs and projects. The main work of the Federal Interdepartmental Task Force on the Potomac has been done at the same time that the new Water Resources Council has been studying out its powers and putting them to use. Formed before the Water Resources Council, the Task Force was assembled as a unique entity rather than as one of the categories of Federal planning organizations mentioned above. But, having been shaped after a directive from the President and having worked in cooperation with the Basin States' Governors' Advisory Committee, the Task Force together with that Advisory Committee has been exercising some of the main functions of a Title II river basin commission. These commissions can plan flexibly, in stages, if this is desirable. They make recommendations for comprehensive development which can quite compatibly be implemented by a separate basin management authority, perhaps of a type recommended by the commission.