Washington — Dan Rostenkowski called for a US trade policy based on a middle ground between free trade and tough but fair protectionism. The Illinois Democrat, chairman of the House Ways and Means Committee, outlined his proposal in a Chicago speech. He said he hoped that a tough, pragmatic trade policy would prompt US allies to return to the international negotiating tables. Among his proposals was stabilization of the world exchange rate system. He urged the international meeting of trade ministers in Paris this week to address this. His remarks were aimed at advocates of free trade, which he called a myth, and protectionism, which he said was a menace.