THERE are already signs that the coming decade will see a rethinking of the meaning and structure of the American political party. The Democrats have appointed a sixty-person commission chaired by Gov. James B. Hunt of North Carolina to propose changes in the procedure for nominating the presidential candidate and allocating delegates to the national convention (it will have reported by the time this article is published). The Republican Party is pledged by a resolution of its 1980 Convention Rules Committee to undertake similar studies; committees chaired by Ernest Angelo of Texas and William H. Stanhagen of Virginia will report on delegate allocation and electoral reform in time for the 1984 convention. John Anderson, who under federal funding regulations could gain several million dollars for the 1984 campaign by converting his National Unity candidacy into a political party, sent out a direct mail circular early in 1981 inviting his contributors to “explore” launching a full-blown party structure. The Citizens Party and Libertarian Party, though their votes were small in 1980, have given talented young activists a lesson in the logic of national party organization. And it cannot be ruled out that leaders of the “new right” will dust off long-standing contingency plans to turn their potent infrastructure of direct mail, broadcast, lobbying, and grassroots organizations into a third-party effort if Republicans fail to deliver on social issues.