What specific constitutionally-protected rights did the federal loyalty programs, investigations, and McCarthy hearings violate?

The House Committee on Un-American Activities has...a very special responsibility. It functions to permit the greatest court in the world—the court of American public opinion—to have an undirected, uncensored, and unprejudiced opportunity to render a continuing verdict on all of its public officials and to evaluate the merit of many in private life who either openly associate and assist disloyal groups or covertly operate as members or fellow travelers of such organizations.”